Futo, Izu, Japan: Futo Hole and sandy seafloor diving

Futo provides a dive profile that balances cavern exploration with open sandy seabed diving. The main attraction, the Futo Hole, is a distinctive grotto found at depths reaching 28 to 30 metres. This overhead environment is celebrated for the way natural light filters through, creating dynamic visual effects within the cavern space. It's a dive that requires careful buoyancy control and an understanding of cavern diving protocols, especially when navigating the interior and observing the light play.

Beyond the Futo Hole, the site unfolds into broad sandy expanses, a different but equally engaging environment. These sand flats are a defining feature of Futo, often compared to the pristine conditions of resort beaches. The clear waters here, particularly when the sunlight is strong, allow light to illuminate patches of anemones and algae, creating vivid underwater landscapes. It’s an area that encourages a slower pace, moving between the defined structure of the hole and the softer topography of the sand.

While the cavern offers its own drama, the sandy bottom is where much of Futo's smaller, resident fauna thrives. You'll encounter Peacock tail soles (Sasauchinoshita), various gobies including the Thick-striped goby (Futosuji Irezumihaze) and White-spotted goby (Datehaze), as well as Pygmy pipehorses (Tatsunoitoko). These species use the sand and scattered growth for camouflage and hunting, often requiring a patient eye to spot their intricate behaviours.

Autumn brings an additional layer of interest, with juveniles making their appearance across the site. Look for juvenile butterflyfish and juvenile boxfish (Shimaumisuzume yg) in sheltered areas, adding to the diversity. The blend of specific macro life with the broader underwater scenery ensures that each dive can reveal something new, whether you're focused on the larger topography or the smaller inhabitants.

The site's position within a bay offers generally stable sea conditions, which contributes to its reputation as a reliable training ground for certification courses. However, don't confuse stability with a lack of features; the depths of the Futo Hole and the diversity of life on the sandy fields mean there's substance for all levels. The visibility here can range, but often provides clear views that enhance both the cavern's light effects and the detailed observation of macro critters.

Among the notable sightings here are various frogfish, including the Red frogfish (Benikaeruankou), which blend seamlessly into their surroundings. You might also find Pygmy seahorses (Himeika) and delicate amphipods (Hosozume Hoteiyokoebe). The combination of a major geological feature like the Futo Hole and the intricate life supported by the sandy bottom and its micro-environments gives Futo its distinct character, separating it from other dive locations in Izu.