You take your shoes off at the door and you do not put them back on until you leave. That is not a quirk of the first room – it is the whole building. You walk barefoot across soft floors, up a sloped wall of falling water, and then into a room where the water comes up past your knees and carries projected koi that scatter when you move through them. Everything here is designed to be walked into rather than looked at.

The two rooms people come for do deliver. Floating Flower Garden is thirteen thousand living orchids hanging from the ceiling, and they rise as you approach so that a dome of space opens around you and closes behind you – you are inside the flowers, not under them. And Crystal Universe is a mirrored room hung with tens of thousands of points of light, so that the reflections run out past where the walls should be and there is no edge to anything.

I went in mildly sceptical, in the way you do about something this photographed, and I was wrong.

What to wear, which is the entire practical question

You will be in water up to your knees. The museum provides shorts to change into if you need them, but the better plan is to wear trousers you can roll above the knee, and to arrive with that already decided.

Do not wear a skirt or a dress. Large sections of the floor are mirrored, which is lovely and also exactly what it sounds like. There are wraps available and staff are gracious about it, but it is an awkward thing to be solving at the entrance.

Bare feet throughout, so a pedicure if you care about such things, and lockers for everything else – bags go in, phones come with you.

Booking

Tickets start around 3,600 yen and the pricing is dynamic, so the same slot costs different amounts on different days. Opening hours run roughly eight in the morning to ten at night, with last entry an hour before close. Weekend and holiday slots sell out, sometimes well ahead, so book before you leave home rather than when you land.

And go early. The eight and nine o’clock slots are the quietest of the day by a wide margin, and this is a place that is genuinely better with fewer people in it – half the rooms depend on your own reflection and movement, and that works less well in a crowd.

Planets or Borderless?

They are different museums and people conflate them constantly. Planets, in Toyosu, is barefoot, wet, physical and follows a set route – about an hour and a half. Borderless, in Azabudai Hills, is shoes-on, dry, and deliberately has no map at all; you wander and get lost on purpose, and it takes as long as you let it.

If you only have time for one and you have children, or you want the orchids and the koi, go to Planets. If you want to disappear into something for three hours, go to Borderless. The Toyosu site is currently listed through the end of 2027, so there is no rush – but check before building a trip two years out.

Getting there

Shin-Toyosu station on the Yurikamome line, north exit, one minute on foot. Or Toyosu on the Yurakucho line, exit 7, about ten minutes. Tap in with your IC card.