Underwater & Underground Stays

Underwater hotel rooms and cave hotels you can actually book. There are far fewer of these than the internet suggests — a good share of the "underwater hotels" that circulate in roundups are renderings, proposals or projects that never opened — so the first question is whether a place exists at all.

Our bar is a bed below the waterline that a paying guest can sleep in. An underwater restaurant, a viewing tunnel or a pool with a window is a fine thing and not a stay, so it does not go in. Cave rooms have to be cut into real rock rather than styled to look like it.

The catch is worth knowing before you book, not after. An underwater room usually means one window rather than a panorama, at a serious premium; an underground one means little natural light and patchy phone signal. Both are extraordinary for a night or two, which is how most people should plan them.

This is also the hub where a dated check earns its keep. Projects in this category announce loudly and open years late, if ever, so a stay shows a checked date only once a person has confirmed it exists, and a stay comes down when it can no longer be confirmed rather than staying up to collect clicks.