Sunflower Ferry launches underwater stamp rally in Japan

Mitsui O.S.K. Lines Sunflower has announced the fourth installment of its ‘Sunflower Hankko Stamp Rally,’ titled the ‘Underwater Stamp Rally.’ Running from October 1, 2026, to September 30, 2027, the campaign shifts focus from land-based landmarks to underwater observatories.

Participants must visit two specific underwater towers: the Okhotsk Tower in Mombetsu, Hokkaido, and the Genkai Kaichu Observatory in Karatsu, Saga Prefecture, located in Kyushu. To complete the rally, participants must also use at least two of the four available Sunflower ferry routes (Oarai–Tomakomai, Kobe–Oita, Osaka–Beppu, and Osaka–Shibushi) and collect digital stamps via QR codes or location services.

Those who complete the challenge will receive a certificate of completion, a limited-edition sticker, and original novelty items. Additionally, participants will enter a lottery for the ‘Sunflower Award,’ which offers prizes such as premium ferry tickets for various routes.