Seiko Prospex Speedtimer Solar Chrono Black SSC957 SBDL121 (SBDL121, SSC957). Current Prices, JDM Listings, Market Analysis

The Seiko Prospex Speedtimer Solar Chrono Black, sold under reference numbers SBDL121 and SSC957, is a solar-powered chronograph sitting in Seiko's Prospex sport lineup. It trades in the US secondary market under both its JDM designation SBDL121 and the international SSC957 reference, giving buyers two search paths for the same watch. Tonbo tracks this model because it shows a consistent price gap between Japanese platforms and the US resale market, which makes it a candidate worth monitoring for arbitrage. The current US median sits at $988, placing it firmly in the upper tier of Seiko sport chronographs.

Current US Market Value

Based on verified eBay sales, the SBDL121 price in the US currently sits at a median of $988. The interquartile range runs from $880 at the 25th percentile to $1,149 at the 75th percentile, a spread of roughly $270 that reflects the normal variation in condition and seller presentation for this model. The comp set here carries a sample size of eight transactions, which is workable for directional pricing but not large enough to call the median ironclad. That said, the sourcing quality for this dataset is rated 🟢 Verified comps, meaning the underlying eBay transactions have been reviewed and filtered for relevance. Anyone researching the SBDL121 for sale on the US market should treat the $880 to $1,149 band as the realistic transaction window rather than anchoring to a single number.

Active JDM Listings

Japanese platform activity for the SBDL121 has been steady in the past two weeks, with listings appearing on both Mercari Japan and domestic Japanese watch dealers. Asking prices range from ¥104,500 to ¥154,800, a wide band that reflects differences in seller type and declared condition. A handful of the lower-priced listings are graded excellent, which is the condition tier that matters most for US resale. Here is what is currently visible in the Japanese market:

• ¥110,000 on Mercari Japan, condition unknown
• ¥119,800 on Mercari Japan, graded excellent
• ¥104,500 on a Japanese dealer platform, graded excellent
• ¥143,000 on Japanese platforms (two separate listings), condition unknown
• ¥154,800 on a Japanese platform, condition unknown

The excellent-condition listings at ¥104,500 and ¥119,800 are the ones worth watching if you are looking to buy SBDL121 Japan. At current exchange rates, those translate to landed costs that can sit meaningfully below the US median depending on shipping and import handling.

Recent Alert History

Two activity-tier alerts fired for this model on May 27, both within the same monitoring window. The first recorded a landed cost of $880 against a US median of $988, producing an 11 percent gross margin. The second came in tighter on timing but showed a landed cost of $779 against the same $988 median, an implied gross margin of 21 percent. Neither alert reached the strict or opportunity tier that Tonbo reserves for higher-confidence setups, but back-to-back activity signals on the same day suggest the model sees periodic sourcing moments worth tracking. You can review current signal tiers across the catalog at tonbomarket.com/signals.

Japan vs. US Price Gap

The US-Japan price gap on the Seiko Prospex Speedtimer Solar Chrono Black SBDL121 SSC957 is driven primarily by the model's JDM distribution pattern. Watches carrying the SBDL121 reference move through Japanese domestic channels and do not always appear in US retail inventory, which limits supply and supports higher secondary market prices stateside. Buyers sourcing directly from Japan and absorbing shipping and proxy fees can land units below the US market floor in favorable conditions, as the May alerts confirm. The main risk factor here is condition variance combined with a thin comp set. With only eight US sales in the dataset, a single below-average condition unit can drag the apparent median, and unknown-condition Japanese listings carry real grading uncertainty until the watch is in hand. Browse active sourcing opportunities across tracked JDM models at tonbomarket.com/deals.

Get Real-Time Alerts for Seiko Prospex Speedtimer Solar Chrono Black SSC957 SBDL121

Tonbo monitors Japanese listings and US comp data for the SBDL121 and fires alerts when landed cost versus market median reaches defined thresholds. If you want to be notified the next time a viable sourcing window opens on this model, alert subscriptions are available at tonbomarket.com/pricing. A free newsletter covering JDM market movements, including models like the Seiko Prospex Speedtimer Solar Chrono Black SSC957 SBDL121, is also available at tonbomarket.com. No manufactured urgency, just data when the numbers are worth acting on.