Prometheus Jellyfish Review

Dive Prometheus Tritium

I’m a big fan of Prometheus watches, so when they came out with their new Jellyfish diver I emailed them right away for a review. There aren’t a lot of watches in this category, so let’s dive right in with the specifications.

  • 14.4mm thick, 44mm wide, 47.2 at the 6.9mm crown.
  • 195g sized to 7.5″ wrist
  • 316L stainless steel case, sapphire crystal with inner anti-reflective coating
  • 90-click unidirection bezel with inset tritium tube
  • Tritium tubes on all three hands and hour markers. Green color except at 12, which is orange.
  • SII NE15A (6R15) automatic movement, handwinding and hacking, quickset date, 40 hour power reserve.
  • Signed, screw-down crown
  • Water resistant to 300m (990ft)
  • 3-link Oyster-style bracelet with screwed, solid links, solid end links, brushed throughout. Clasp is snap closure with signed fliplock and 3 microadjustments.

Most of the tritium watches we’ve reviewed have quartz movements. (See here for a list) There are several reasons for this: tritium-tubed hands require more torque from the movement, the additional cost of the automatic movement and reduction in durability compared to quartz. Recently we’ve started seeing automatic divers with tritium: A new Luminox, the Christopher Ward Tri-Tech, Marathon GSAR and Deep Blue. To this short list we can now add the Jellyfish.

One of the things I quite like about the Prometheus watches I’ve reviewed is their consistently uncluttered and readable dials and designs. A lot of new brands put lots of text on the dial; the Jellyfish has only a small logo and the brand name. Wonderful! Even the caseback is an etched Jellyfish, a nice change of pace from some of the macho model names I’ve seen.

In the closeup here you can see how the tritium works. Tiny glass tubes, about 1mm across, are inset into the dial and hands. You have to peer pretty closely, from a normal viewing distance it looks like applied markers. Notice how the tubes increase the thickness of the hands, because of this the dial is set a bit deeper below the crystal and the rehaut is a few millimeters taller to make room.

The Jellyfish is available with black, white yellow or blue dial. In white or black it’s most versatile and would make an excellent do-anything watch. In yellow it’s more of a casual timepiece, quite fun to wear.

Tritium is interesting if you’re used to Superluminova. Not as bright as full-charge conventional lume, the constant brightness can be quite startling in the early hours of the morning. Paired with the black-on-yellow hands, and anti-reflective sapphire crystal, and this is a watch with outstanding day or night visibility and legibility.

This is my first watch with the SII NE15A. Introduced in 2007, this is a competitor to the ubiquitous ETA 2824 and I’m quite pleased. Smooth to handwind, no rotor noise, fast date change, excellent timekeeping, good date wheel alignment, it’s a great movement and in my opinion is at least as good as the competition Miyota 9015 and ETA 2824.

The case and bracelet are brushed finish of very high quality. I like here how the crown guards extend all the way to the end of the crown and flow smoothly from the side of the case. You can also see how the bezel is nicely grippy and protrudes for easy usage. The crown is midsized a 6.9mm, and has an etched logo. Action is very smooth, though as you can see on the video you have to be cautious engaging the first thread. (I’ve only seen one watch that didn’t have this problem; threading is just plain tricky.)

Sized for my 7.5″ wrist, the Jellyfish is a substantial 195g. Not a heavyweight, but you’ll notice it there. As with most, the weight of the bracelet balances it out nicely.

Notice how you can read the time quickly, and how the date window at 4:30 is visible but unobtrusive. The uncluttered yellow dial reminds me a bit of the Halios Holotype,another nice design. Also note how they rotated the tubes at three, six and nine to make room for an Arabic numeral. Simplicity is harder than it looks.

The bracelet is excellent, and at this price point I was taken aback. Screwed links, solid end links, signed clasp and lots of extra links, no squeaks or rattles here. The clasp is heavy gauge metal, with machined parts, fixed-length wetsuit extension and four microadjustments for a perfect fit. About the only thing I might change is a pushbutton release instead of snap, but that’s a pretty trivial detail.

As suits a solid watch, the bracelet is non-tapering, which helps keep it from shifting around on the wrist. The brushed finish is low-key and businesslike.

Notice how the clasp is low-profile; this is more comfortable for those of us that spend all day on a keyboard as it doesn’t dig into the wrist.

The bezel is great. Easy to use, even when wet, with 120 clicks and markers all the way around, plus tritium pip at 12.

At this point you might question my enthusiasm for the Jellyfish, so I should explain that it costs just $345 (non-EU price). At that price, it has no competition, and the quality is amazing. You really cannot go wrong here.

I personally like the cheerful yellow dial, but it’s a less versatile color and would be a stretch to wear in a formal environment. More of a summer, casual-Friday look. The black or white dials would work better for that, or perhaps the blue variant.

There aren’t a lot of watches I can recommend like this one. The price is fantastic, the quality amazing, and the style is versatile enough for most occasions. A bit sporty for the truly dressy, if anything, the combination of automatic movement and tritium illumination also excels at starting conversations.

Highly recommended.

Our thanks to Prometheus for the review loaner.

By Paul Hubbard


  1. Paul, First of all, awesome review! I am in love with the beautiful and understated design of the Jellyfish. Using tridium is a very interesting choice. I have a few handguns with tridium sites and it is highly visible. What amazes the me the most about this watch is the price. $350?? What a great deal on a very high quality and versatile watch. I predict these will be going for much more in the next few years.

  2. WTF?

  3. 6R15 with AR Sapphire for $350? What a deal! I have a Seiko Sumo, which also uses the 6R15 movement and it’s great. However, many people wish it had a better bracelet (Sumo’s is 20mm that tapers to 18mm) as well as Sapphire crystal. This has both and is about $200 less! Also tritium tubes interest me since they don’t really fade and don’t need a light source to charge them (although, I love Seiko’s lume). With this review the Jellyfish may have jumped to the top of my wish list.

  4. Thanks for the info on the watch. That video was pretty ridiculous, but I guess in the end you did get to see it live, and that’s the point.

  5. Awesome review. Based on your review I purchased a black dial Jellyfish and couldn’t be happier. Considering what you get (6r15 movement, tritium lume, sapphire crystal and solid SS case and bracelet) for $350 you can’t go wrong. I can see me wearing this watch with a suit – both swim and tailored. I think the best way to describe the Jellyfish is “understated elegance”. It has everything you need. Thanks for doing such a thorough review.

  6. This is one very nice looking watch even with the yellow dial. I guess the yellow looks good because it’s sort of pale and not very bright which would ruin it. Very nice polished case and bracelet and some very impressive specs. Could we please have a test to see what the accuracy rate of this watch is?

  7. Got a white Jellyfish and couldn´t be happier.
    The watch is very precise for a mechanical watch, no problems there for sure. 😉
    Like others said, the specs of this watch makes it a great bargain, it´s a great watch at this price! 🙂
    Highly recommended indeed!


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