Which is cheaper, the Seiko Prospex Sea or the Spinnaker Croft Mid-Size Skeleton?

At MSRP the Spinnaker Croft Mid-Size Skeleton is the cheaper of the two at $425, against $1,100 for the Seiko Prospex Sea — a $675 gap before any retailer discounting.

Which is bigger, the Seiko Prospex Sea or the Spinnaker Croft Mid-Size Skeleton?

The Seiko Prospex Sea wears larger at 41.3mm versus 40mm for the Spinnaker Croft Mid-Size Skeleton — a 1.3mm difference across the dial.

Which has better water resistance, the Seiko Prospex Sea or the Spinnaker Croft Mid-Size Skeleton?

The Seiko Prospex Sea is rated to 300m versus 100m for the Spinnaker Croft Mid-Size Skeleton.

Which has a longer power reserve, the Seiko Prospex Sea or the Spinnaker Croft Mid-Size Skeleton?

The Seiko Prospex Sea carries a 72-hour power reserve against 40 hours on the Spinnaker Croft Mid-Size Skeleton.

What movement does the Seiko Prospex Sea run compared to the Spinnaker Croft Mid-Size Skeleton?

Both watches run automatic movements — the Seiko Prospex Sea uses the 6R55 and the Spinnaker Croft Mid-Size Skeleton uses the SII NH38A.

Side by side

Seiko Prospex SeavsSpinnaker Croft Mid-Size Skeleton

The numbers, the dial colors, the calibers — laid out so you can stop flipping between tabs.

Seiko Prospex Sea

spb481j1

MSRP $1,100

Spinnaker Croft Mid-Size Skeleton

croft-mid-size-skeleton-automatic-spongebob-squarepants-peek-a-boo-limited-edition-dollar-diver-sp-5152-01

MSRP $425

At a glance

13 of 29 specs differ

Diameter

Prospex Sea41.3mm

Croft Mid-Size Skeleton40mm

Power Reserve

Prospex Sea72h

Croft Mid-Size Skeleton40h

Water Resistance

Prospex Sea300m

Croft Mid-Size Skeleton100m

MSRP

Prospex Sea$1,100

Croft Mid-Size Skeleton$425

Full specifications

Case

6 specs

Crystal & Dial

3 specs

AR Coating

Anti-reflective coating on inner surface

Inner

Dial Color

Black

Dollar Diver

Lume

LumiBrite on hands, index(es) and bezel

None

Movement

3 specs

Caliber

6R55

SII NH38A

Power Reserve

72h

40h

Jewels

Pricing

1 specs

MSRP

$1,100

$425

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What people say

Owners + reviewers, side by side

Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.

Seiko Prospex Sea

Seiko Prospex Sea models are widely praised for their excellent build quality, value for money, and comfortable wearability, with many appreciating the vintage-inspired designs and robust construction. Owners note the silicone straps are surprisingly comfortable and well-finished, and the Lumibrite lume is excellent. However, some find the 44.3mm size and thickness too large for smaller wrists, though others report the sizing as perfect. The 6R15 movement in some variants offers accuracy around +4 seconds per day with a 50-hour power reserve, while newer movements offer more. Some models are criticized for a bracelet width not matching the case size or a rudimentary clasp for their price point. Overall, owners and reviewers rate the Seiko Prospex Sea highly for its impressive case work and finishing at its price point.

A Blog to Watch·6

Spinnaker Croft Mid-Size Skeleton

The Spinnaker Croft Mid-Size Skeleton is noted for its 40mm steel case, sapphire crystal, and 150m water resistance. One owner reports strong performance from the TMI NH70 movement at -3 seconds per day, with very nice lume. On balance, owners find the Spinnaker Croft Mid-Size Skeleton to be a pretty nice option, particularly for its movement performance and lume.

WatchUSeek·2

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