Swatch built this watch twice, two weeks apart, and made the second one hide what the first one shows.
The Full Moon came first in white Bioceramic, with the cartoon detail sitting on a pale moonphase disc where you can see it. Then came the New Moon: all-black Bioceramic, and a black moonphase disc under a black semi-transparent mask — the same complication, deliberately obscured, because a new moon is the moon you can't see. Swatch even rotated the display. The aperture sits at 2 o'clock on both watches, but it runs horizontally on the Full Moon and vertically on this one.
Technically the two are the same watch. In practice one shows you its best feature and the other conceals it — which changes the strap question completely.
The size: 20mm
Every MoonSwatch takes a 20mm strap, this one included. Same case across the whole collection, so there's nothing to measure and nothing to check.
And worth knowing before you shop: our mission collections are a colour menu, not a compatibility list. Every MoonSwatch strap we make is 20mm with the same 126mm and 78mm lengths, cut for the same 42mm case. A strap filed under the Full Moon or Neptune fits your New Moon exactly as well as one filed here — which matters on this mission more than most, because two of the picks below come from elsewhere.
When you take the colour away, only texture is left
Here's what's different about strapping an all-black watch, and it's the thing nobody mentions.
On every other mission the strap is a colour decision, and colour is loud enough that you never really look at the material. Take the colour out entirely and there's nothing left to look at but the material. A fuzzy hook-and-loop nylon band against a fired ceramic case is a texture mismatch on any watch — on this one it's the only visible difference between the two halves of the assembly, because they're both simply black.
That's the case for rubber here, and it isn't about wear or durability. It's that black-on-black is the one configuration where a cheap-feeling material has nowhere to hide.
The second half of the argument is the complication. This watch already hides its best feature behind a mask; if the strap says nothing either, the whole thing disappears. So the strap becomes the only place the watch can carry any information at all — which is exactly what the picks below are organised around.
One practical note. Bioceramic is hard but marks more easily than steel, and the case is a monobloc that can't be sent away for a tidy-up — so work on a soft cloth, keep the spring-bar tool square to the bar, and keep metal away from the case flanks. On a matte black case, a bright scratch shows more than you'd expect.
The best straps for the Moonphase New Moon
1. Black with a white line — one line of information
The right amount of speech for a watch built on concealment. A black strap with a white line is almost entirely dark, with a single bright element running its length — so the watch stays stealthy but stops being invisible, and the eye has one thing to follow down to the buckle. It's also the configuration that photographs, which matters on a watch that otherwise reads as a black disc in most light. Start here.
2. Black on black — the stealth version
Commit to the idea. A tone-on-tone black strap gives you a completely uninterrupted black object from lug tip to buckle, and because there's no colour anywhere, the only thing your eye can register is surface: the smooth sheen of rubber against the matte of ceramic, and the faint change of tone where the strap meets the case. That's a subtler, better-made version of exactly what the factory band was reaching for, and it's the most genuinely stealthy this watch gets.
3. White — wear its twin
The one that makes people look twice. Swatch built these two watches as a pair, so putting the Full Moon's white strap on the New Moon inverts the relationship on purpose — a black watch on a white band, opposite a white watch on a black one. It's the single most striking thing you can do with this reference, and the plain white strap is filed under the sibling mission, which is precisely the point made further up.
4. Blue on blue — what a moonless night actually looks like
A styling call rather than a colour match, and the more interesting for it. A moonless sky isn't black; it's a very deep blue, and a tone-on-tone blue strap reads almost black in low light while staying unmistakably blue in daylight. On a watch named for a dark sky that's a quietly clever pairing, and it gives you a version of the New Moon that isn't monochrome without ever becoming bright.
The short version
20mm, like every MoonSwatch. Black with white for one line of information, black on black for full stealth, white to wear its twin, blue for the colour a night sky actually is.
Every strap in our Moonphase New Moon collection is cut for this case, ships with spring bars included, and carries a lifetime warranty on rubber — with free worldwide shipping and no import costs, part of why more than 50,000 customers have trusted us with their watches. There's a full MoonSwatch strap guide covering every mission if you own more than one. Helvetus is not affiliated with Swatch AG or Omega SA.
