Casio has expanded its Oceanus Retro Tone Collection with two Japan-only limited editions for August 2026: the Manta S400 OCW-S400RL-8AJR and Classic Line OCW-T2600RL-3AJR. Both use lightweight titanium cases, solar power, radio-controlled timekeeping and Tochigi leather straps. The idea is simple: modern Casio technology presented with warmer colours and a more traditional character.

The Casio Oceanus Retro Tone Collection pairs the green T2600 with the grey Manta S400. Image: Casio.

A Softer Retro Tone Look

Both watches use half-matte gradient dials that change gently from the centre to the outer edge. Casio creates the effect through a silver layer, colour coating and printed gradient pattern while keeping the dial transparent enough for solar charging. Straight hands and solid bar markers keep the displays clean. The vegetable-tanned cowhide straps come from Tochigi Leather, a Japanese maker founded in 1937 and should soften and develop a darker colour with use.

The Lighter Manta S400

Casio Oceanus Manta S400 OCW-S400RL-8AJR with its grey gradient dial and rose-gold-coloured sapphire bezel. Image: Casio.

The OCW-S400RL-8AJR is the smaller and more expensive model. Its titanium case measures 46.5 mm long, 41.3 mm wide and only 9.2 mm thick. Without a bracelet, the watch weighs just 38 grams. A frosted sapphire bezel ring carries world-time city codes and receives rose-gold ion plating. The dial is grey, giving the warm bezel and brown leather strap plenty of room to stand out.

At only 38 grams, the titanium Manta S400 should feel especially light on the wrist. Image: Casio.

A dual-curved sapphire crystal has anti-reflective coating on both sides, while titanium carbide treatment helps protect the case from scratches. Water resistance is 100 metres. Tough Solar power works with Multi-Band 6 radio reception and Bluetooth through the Casio Watches app. The app supports automatic time correction, easy settings, phone finding and watch status checks. A full charge lasts about five months without further light, or roughly 19 months with power saving. Without radio or phone correction, standard quartz accuracy is rated at ±15 seconds per month.

The S400 combines a frosted sapphire bezel ring with a vegetable-tanned Tochigi leather strap. Image: Casio.

More Functions from the Classic Line

Casio Oceanus Classic Line OCW-T2600RL-3AJR with its green gradient dial and full analogue display. Image: Casio.

The green OCW-T2600RL-3AJR measures 48.2 by 42.8 by 10.7 mm and weighs 49 grams. It also has a titanium case with titanium carbide treatment, a sapphire crystal with anti-reflective coating on both sides, 100-metre water resistance and a brown Tochigi leather strap.

The 42.8 mm T2600 on its brown Tochigi leather strap. Image: Casio.

This model drops Bluetooth but adds a fuller analogue display. It offers world time across 29 cities and 29 time zones, UTC display, automatic summer-time adjustment, a 1/20-second stopwatch measuring up to 60 minutes and day and date displays. Multi-Band 6 keeps it accurate where compatible radio signals are available. Its full-charge figures are about five months in normal use or 22 months with power saving.

The green dial changes from the centre to the outer edge, while the leather should develop its own colour with use. Image: Casio.

Prices and Availability

Casio plans to release both watches in Japan during August 2026. The Manta S400 is limited to 300 pieces and costs ¥165,000. Using European Central Bank reference rates from 31 July, that equals about $1,030, €897 or £767. The Classic Line T2600 is limited to 500 pieces at ¥115,500, approximately $721, €628 or £537. These are currency conversions, not official prices outside Japan and importing either model may add taxes and fees.

Both Japan-only Oceanus Retro Tone limited editions come in special presentation boxes. Image: Casio.

Conclusion

The S400 is the cleaner and lighter choice, with Bluetooth and that cool sapphire bezel. For value, I would choose the T2600. It costs less, adds world time and a stopwatch.