Collector Guide The Rolex Explorer II (All References In Detail)

The original Rolex Oyster Perpetual Explorer II debuted in 1971. Fifty years later, it’s accurate to say that the Explorer II was a flop at its launch. The intended purpose (or at least marketing position) of the Explorer II at inception was a watch for use while spelunking. The explorer spirit is certainly present in exploring caves. It’s dark, it’s damp, and potentially dangerous. Despite a rise in popularity during the 1960s and 1970s, spelunking didn’t prove popular enough for the general market to identify with or provide an experience to daydream about. The original Explorer II was simply an ugly duckling with minimal practical application packaged to the general public as a luxury tool item. A dud.

Success can take decades. This collector’s guide will take you through all the Rolex Explorer II references so that you can understand the details of each generation of this iconic watch. Rolex is very large scale luxury timepiece manufacturer. Due to batch manufacturing and mid-year releases, many references overlap in calendar years as well as movements and parts. There is no magic switch that changes the reference model numbers at midnight on December 31st. Rolex is also very tight-lipped about information and does not offer an official stance on much besides the published specs of whatever is in their current catalog.

Reference 1655 (1971-1984)

• 39mm
• caliber 1575
• large orange 24-hour hand painted tritium indices
• black dial only
• lines between even numbers on the bezel
• 4 distinction version distinguished by bezel differences

The Rolex Explorer II 1655 has a 39mm case. The most distinguishing characteristic of the 1655 is the steel 24-hour bezel. The bezel is fixed. That differentiated the Explorer II from other Rolex sports models of the time like the Submariner and GMT Master (both of those models had rotating bezels with aluminum inserts). There was also no bezel insert on the Explorer II. This was a design shift for Rolex sport (Professional) models such as the GMT Master and Submariner. The steel 24-hour bezel remains unique to the Explorer II at present.

The Explorer II 1655 was part Explorer 1016 and part GMT Master 1675 combined to look similar to a sighting compass. The sighting compass (with in inclinometer) was an important tool used by spelunkers for mapping and surveying caves. Radio signals for audio and data purposes don’t work well underground. The analog technology of caving remained relevant well into the modern digital era.

The other unique feature that Rolex introduced in 1971 with the Explorer II was the compass-like stubby orange 24-hour hand. The hand was deliberately stubby so that it could hold more tritium lume, which was essential for those crawling through pitch dark caves with only the primitive lantern batteries of the time. The presumption was that the 24-hour hand would operate solely as an AM/PM indicator, so it it always locked to the main time as shown on the two hands.

The most desirable variant of the 1655 is the Mk III dial known as the “Rail Dial”. On the lower portion of the Rail Dial, the words “SUPERLATIVE CHONOMETER OFFICIALLY CERTIFIED” are positioned so that the C’s are aligned. You will need to pay more for that extra bit of text alignment, which may seem a bit silly, but this kind of obsession over details often grows into legendary treasure hunts among Rolex collectors.

One of the biggest practical shortcomings for the 1655 was Rolex’s use of the caliber 1575 movement. This the same movement as the 1570, but with the addition of a date wheel. This automatic movement was shared with Rolex GMT Masters of the same era. At the time, there was no jumping local hour hand in the Explorer II or the GMT Master. The hour and hand the GMT hand were geared together and couldn’t be uncoupled by manipulating the crown. With the GMT Master, the local time was set and the 24-hr bezel was rotated to the appropriate second time zone use the position of the GMT hand as the home time reference. This functionality was not present on the Rolex Explorer II 1655 as the bezel was fixed and could not be rotated. With the Explorer II 1655, AM and PM was all you got.

The local jumping hour hand had not been developed by Rolex yet, making quick setting the local time difficult. The caliber 1575 was still impressive for its day with a power reserve of 48 hours and instantaneous date change. If properly serviced it can still be regulated to within COSC (official Chronometer) specs today.

Rolex ceased 1655 production in 1984 with some leftovers creeping into 1985 sales. There was no commercial success for the 1655 and many of the watches sat in deadstock at retailers.  Collectors love this model because it is so different when compared to the more conservative Rolex models, both past or present.

BEWARE: Prospective buyers really need to do their homework on the Explorer II 1655 before purchasing. There are seven dial variants, four bezel variations, two movements, and three bracelets to sort through. It’s extremely difficult to assess the originality of those combinations to ensure everything is correct. The watch may be all authentic Rolex parts for the reference, but the dial and bezel could be service or replacement parts. It is important to know what your personal tolerances are for original parts.

Rolex Explorer II Ref 1655: Five Facts 

1. There was no lollipop seconds hand on the MK I’s (1971-1972) 

2. The MK VI service dial (1984 on) used Luminova and were marked “SWISS” 

3. There are four different bezel variants 

4. The 1655 is nicknamed the “Steve McQueen” despite having no connection to the actor 

5. There are thirty-five points of lume on dial and hands. (MKII-on) 

Reference 16550 (1985-1989)

• 40mm
• caliber 3085
• white gold surrounds on hour markers
• black or white (faded to cream) dials

“Transitional” is the word that usually describes the Rolex Explorer II Ref 16550, as Rolex pivoted their catalog in the early to mid-1980s toward the emerging return to luxury and ostentation that marked the decade. The professional (tool) watches saw the biggest changes. Glossy dials and white gold applied hour markers solidified the Rolex luxury market position. The 16500 was available in white and black dials. Both dial colors had paint defects that are very desirable to collectors. The white dials tend to age into a cream color. A paint defect on the black dial causes it to crack (“spider”). The defects and deteriorations actually add to the value and collectability of the watch.

While the Explorer II followed Rolex’s path upmarket, it was transitioned from the useless cave-dweller to something worthy of wrist time on a grand expedition many time zones away from home. Expedition to where? Letting your imagination run wild is part of the fun, and Rolex didn’t specify a specific sport any longer.

The Explorer II ref 16550 featured the Rolex caliber 3085 automatic movement. The game-changer was the jumping local-hour hand to track local time while the 24-hour hand tracked the time at home. Do you recognize that long and slender 24-hour hand (hint: GMT Master)? The Explorer II could now step out of a cave and onto an airplane destined for the far reaches of planet Earth. 

In order to make the hour hand jump independently the caliber 3085 has to be a little thicker to accommodate the complication. You will often hear of GMT Master II’s that share the 3085 called “Fat Ladies”. The power reserve remained at 48 hours.

The case diameter was upped from 39mm to 40mm, although the case size is debated by some to still be 39mm; it’s a negligible difference. In contrast to the luxury market position, the Explorer II 16550 kept true to tool watch features by retaining the drilled lugs of ref 1655. The new case was very similar to the GMT master as well. The big differentiator between those two models was the bezel. The 16550 replaced the odd hour line markers of the 1655 with arrows. This feature is still present on the bezel today.

The drilled lugs make removing the bracelet easy if you want to change to a strap. That’s great because you’ll probably want to. The bracelets for the 16550 aren’t great, especially the early ones. Your best bet is a later production bracelet ref 93150 with the locking clasp. You will still have to settle for hollow endlinks (593 or 501B). These bracelets are also shared with the GMT Master from that era.

BEWARE: Since bracelet swapping is common, make sure that you check the endlink numbers, clasp code, and bracelet reference before paying top dollar for an excellent example.  

Rolex Explorer II Ref 16550: Five Facts 

1. The 16550 was available with black or white dials 

2. The early white dials featured white gold surrounds on the indices

3. Most white dials have aged to a cream color 

4. The caliber 3085 moment was shared with the GMT Master II 

5. It was the first Explorer II that could track a second time 

Reference 16570 (1989-2011)

• 40mm case
• cal 3185 with Nivarox hairspring
• skinny red 24-hour hand
• black or white dials

Chances are if you’ve seen an Explorer II on social media or on offer from a watch dealer in the last few years it was a ref 16570. Rolex produced this reference for over two decades. This was one of the longest runs in Rolex history.  Rolex does not publicly share production quantities, but it is somewhere between a boat-load and a shit-ton (technical terms, of course).  

Due to many aesthetic similarities with the previous model (16550), many people’s perceptions blend the two references together. The Explorer II 16570 retained many details from the 16550 such as the 40mm oyster case, 100m of water resistance, white or black dial options, jumping local-hour hand, and brushed fixed bezel, and red thin GMT hand.  

When you hear a watch referred to as “Polar Explorer”, the reference 16570 with a white dial is what they are talking about. The white dial with contrasting black hour markers, hands, and text is compared to the visuals found at both poles of the Earth. Throw in the GMT hand that is red like a survival suit and you have a virtual expedition on your wrist. 

This reference can be subdivided into four distinct eras. 

16570 Version 1 – (1989-1997) Features “SWISS – T<25” Dial, 3185 movement, drilled lugs case, pressure bracelet clasp

16570 Version 2 – (1998/1999 features “SWISS” Only Dial, 3185 movement, drilled lugs, locking bracelet clasp

16570 Version 3 – (1999-2005) features “SWISS MADE” Dial, 3185 movement, drilled lugs, or no-holes case

16570 Version 4 – (2005-2011) features “SWISS MADE Dial, 3186 movement, no holes case, rehaut, solid endlinks, locking bracelet clasp

16570 Version 1

Assuming the dial is original, that is the best place to start to assess the Explorer II. The earliest versions of the reference 16570 still had tritium lume markers. This easy to identify by the bottom of the dial, “SWISS – T<25”, at the six-o’clock position. The tritium lume is surrounded by white gold hour markers and hands. This is also found on the white dial version because those white gold markers and hands are covered in black enamel. The white gold boxes stay untarnished as the tritium and it degrades. This is why you see many of these with rich custard colored patina.  

There are a few things to keep in mind with these highly collectable T<25 Explorers. The hands and hour markers should not have matching patina. Hands and hour markers do not age at the same rate. Furthermore, if the hands have no patina, they are most likely service hands (Luminova). Check them with a UV flashlight. If the lume is great, chances are they have been replaced during a service. Don’t set your expectations high for the bracelet. Correct bracelets (78360) have hollow endlinks (501B) on these early T<25 models.

Another criticism of the early Rolex Explorer II’s was the 3185 movement. Many have found it unrefined due to how the GMT hand wiggles (ever so slightly) as you jump the local hour hand.  Despite failing the very technical “wiggle test”, the 3185 movement is a reliable in-house movement that was completely manufactured by Rolex, with the exception of the Nivarox hairspring. The power reserve on the 3185 is 50 hours.

16570 Version 2

In 1998 Rolex ceased the use of Tritium lume in favor of Luminova. These watches are a rare middle-sibling within the 16570 reference. If the hands have much stronger lume than the hour markers, chances are that they’ve been replaced with Super-Luminova service hands and are not original. When you hear the term “Swiss Only” with Rolex, it means that the dial has “SWISS” printed at the six o’clock position of the dial. This is found in the 1998 model year 16570s and ran into 1999 (some A-serial numbers). For a 1998 remember to check the serial number (U) and bracelet clasp code (Z or W) to avoid any shenanigans.

The bracelet also changed during this third iteration to include the flip-lock clasp. The 78790 bracelet was also used on the GMT Master II of the same era and it was basically the same as the Submariner bracelet, just without the dive-extension.

16570 Version 3

The next in the evolution of the Explorer II 16570 was the use of Super-Luminova starting in 1999. These examples of the 16570 will have “SWISS MADE” at the six-o’clock position on the dial. During the era, the 16570, as many Rolex models did, transitioned from drilled lugs to a no-holes case by the end of 2002. There was no hard stop and the difference in many sports models was not by serial number, but by batch.

The trickiest part of the third era of Explorer II 16570s is deciphering the correct bracelet/ endlinks combinations for the year. During this time period you will see no-holes cases with Y serial numbers (2000). However, you will also see correct holes-cases (drilled lugs) with as late as 2003 manufacturing dates. To make it more confusing, solid endlink bracelets started to appear in this same timeframe. They overlap during those same there years. Be very careful of solid enlinks intended for the drilled-lugs case being swapped into a no-holes case. That common mistake can only be remedied by having the endlinks be drilled out. The rule is if you can’t see the springbar though the back of the end link, its meant for a drilled-lug case.

If you are into patina this is not the version to get as the Super-Luminova will keep those indices nice and white while the watch ages. Super-Luminova will look green when active. This era is currently the most abundant and readily available. Despite the availability of models from this era, be prepared to pay the ever-rising market price.

16570 Version 4

In 2005-2006 the Explorer II received the final upgrades of its 5-digit production run. The most significant was the upgrade to the caliber 3186 Rolex movement. The GMT hand wiggling was now a thing of the past. There are some 2005 watches with the rehaut with 3185. Always do the wiggle test to be sure. The 3186 introduced the Parachrom hairspring that offered more protection from shocks and temperature changes. The power reserve remained at 50 hours.

Other upgrades included a laser-etched rehaut (as seen in present Rolex models) At this point drilled lugs were gone and the all the bracelets had solid endlinks (SEL). The upgrades had become so significant that despite most 16570s looking same from six feet away, the Explorer II had fully accepted its place in luxury status. That’s not an insult, the last years of the Explorer II ref 16570 represent the apex of classic sports Rolex. Without question, they are on the top of the shortlist for a one-watch collection.

Rolex Explorer II Ref 16570: Five Facts 

1. The last of the tritium dial Explorer II’s 

2. White (Polar) dials had black surrounds on the hour markers.  

3. Available in drilled lugs and no-holes cases 

4. The caliber 3186 moment upgraded (2005/2006-on) 

5. 22-year production run  

Reference 216570 (2011-2021)

• 42mm case (sometimes called a Super Case, or Maxi Case)
• caliber 3187
• black or white dial
• large orange 24-hour hand
• Chomalight lume

Updated in 2011, this one is a whopper, the Rolex Explorer II ref 216570 received the controversial “maxi treatment” as consistent with other Professional models in the catalog. Rolex calls this the Super Case. A 42mm diameter case, wide lugs, thick crown guards, and larger hour indices enhanced the wrist presence of the six-digit Explorer II. The hour and minutes hands are wide and stubby and have been called “cartoonish”. This massive update in 2011 was the unofficial way for Rolex to celebrate the 40^th anniversary of the Explorer II model.  

Rolex pulled out all the stops to modernize the Explorer II. It received the in-house caliber 3187 that is unique to the Rolex Explorer II ref 216570. The caliber 3187 is very similar to the 3138, just slightly larger to fit the larger 42mm case. This automatic dual-time movement is not shared with the GMT Master II. This is a big move for Rolex. Historically, they have used the same movements (with slight tweaks) across many different models. The power reserve for the caliber 3187 is 50 hours. That was the industry standard for 2011, though many brands now offer 70 hour power reserves (including Rolex).  

Like the previous two generations before it, the Explorer II ref 216570 came in two colors: black dial with silver (white gold) hands and hour markers and white dial version with black outlined hands and hour markers. The black hands over a white dial are something that you don’t even get on a Daytona and they remain a highlight of the Explorer II.  

Modern upgrades to the Explorer II include the use of Rolex’s proprietary lume called Chromalight. It is used on the hands and hour markers. Chromalight is blue in color when activated (as opposed to the green glow of SuperLuminova). The human eye is more sensitive to blue wavelengths than green. This makes the Chromalight-treated modern Rolex Professional models appear brighter than those with SuperLuminova.  

The modern Rolex Oyster bracelet on the six-digit Professional line is something special. They are so solid that the wearers are spoiled to the point that all other bracelets become subpar. The 20mm Superoyster bracelet found on this generation is brushed with a milled clasp. It also has on-the-fly adjustability in 5mm increments with Rolex’s “Easylink” system. The bracelets on five-digit vs six-digit reference Rolex models are night and day. Plan your expectations accordingly.  

Despite all of the changes, Rolex kept pieces of the original’s 1971 DNA intact. One of the key features to return was the stubby orange 24-hour hand. It is important to note the black dial versions have a black base to the, hour, minute, and 24-hour hand while the white dial versions do not. Rolex also resisted their own trend of ceramic bezels and the Explorer II ref 216570 retained the fixed steel 24-hour bezel with signature radial brushing. All of the upgrades didn’t seem to be enough. The Explorer II 216570 was one of the last all-steel Rolex Professional models available in the display cases at authorized dealers. Eventually, there were all gone too. It’s never fun being picked last. 

Rolex Explorer II Ref 216570: Five Facts 

1. 42mm diameter “Super Case” 

2. Chromalight Lume 

3. Superoyster bracelet with milled clasp 

4. Unique Rolex Caliber 3187 movement 

5. Large and stubby orange 24-hour hand  

Reference 226570 (2021-present)

• 42mm case (sometimes called a Super Case, or Maxi Case)
• Caliber 3285
• Black or white dial
• Large orange 24-hour hand
• Upgraded Chomalight lume
• Enamel dial

Despite all the hoopla predictions for the Explorer II’s 50th anniversary, Rolex didn’t put a ceramic bezel on the new version. In fact, the upgrades are relatively mellow, and aesthetically almost invisible. The dial is now enamel, which will shine a little more brightly in white and will give the black dial a bit of depth. The lume is said to be better, as well, and some of the lugs and bracelet dimensions have been tweaked (similarly to how the new Sub was tweaked for 2021).

The biggest news is that the Explorer II now has the up-to-the-minute Caliber 3285, distinguished most fully from the former movement with its 70-hour power reserve, but also more subtly with upgraded a-magnet components in key positions to help achieve and maintain Rolex’s strict Superlative Chronometer rating of -2/+2 seconds per day.

For fans of the previous iteration of the Explorer II, the faithful aesthetics of the 226570 will be a delight, and it may prove difficult to distinguish the previous model from this new one at a distance.

Conclusion 

No matter what the reference or era, the Rolex Explorer II is a unique watch. Changes in perception have impacted the prices for these models on the pre-owned market. Rolex will always have plenty of mainstream swagger, but enthusiasts are the ones that really drive the moving target that determines the sweet spot for pre-owned Rolex. 

I would be remiss to not acknowledge the impact that watch journalists have had on these watches, particularly the reference 16570. It doesn’t hurt that these watches look spectacular on social media, especially the white (“Polar”) version because white dials are so photogenic.

2021 marked the 50^th anniversary of the Explorer II. The Explorer II is one of the few Professional models from Rolex that still comes in steel only. Rolex has a tendency to give enthusiasts what they want while twisting the knife at the same time. Rolex played it extra-safe with the unofficial 50th anniversary ref. 226570. It will be interesting to see how popular these will become. Rolex brings the color orange to the design of the Explorer II and the Milgauss.

There are no more new Rolex Explorer II’s sitting in stock at ADs and pre-owned dealers can turn over the vintage models with ease. The secret is out. It only took fifty years for everyone to figure it out. The dud has finally bloomed into the stud.

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