Basically Spa World is a spa theme park with a hotel and restaurants all in one location. I stayed 2 nights in the annex which is the newer section of the hotel easily accessible from the main building by a walkway. As soon as you enter SpaWorld you are meant to put your shoes into a shoe locker. If you are staying overnight and don’t want to bother just take off your shoes and bring them to your room. My room was tiny but super clean, The bathroom was perfect and had a toilet that does much more than flush, basin and shower. The room itself was not much bigger than the bed but had a TV and chair, fridge and heaps of plugs. I was alone so it was fine. The room was only 7200 Yen per night which was a very low price I thought as the room includes the buffet breakfast and entry to the spas. Breakfast had lots of choices both western and Japanese and was really quite good. Note very few of the staff speak much English so best to use Google Translate on your mobile phone which seems to be best option. Most of the staff used that or another translate site to communicate. The spas are separated by sex. The women have one floor and the men another floor which changes every month I believe. The pool is on the top floor but be aware it is meant for families and kids. There is no proper lap pool where you can swim laps. I went to do that but had to swim inside the kiddie loop that surrounds the water slides. When you enter the spa level there are lockers which require a 100 yen coin but you get the coin back after you are done. There is a machine that dispenses 100 yen coins if you do not have any. You put ALL of your clothes and gear into the locker and the the only thing you are meant to bring into the spa area is your naked self and a small yellow towel which they provide. You are meant to wash yourself thoroughly before you enter any of the pools. There are many washing stations throughout the spa floor. The spas are separated into country themes such as Persia, Turkey, Bali, Singapore and Japan. Each pool has a temperature readout and there are at least 2 cold pools to cool off. The Japanese area was outdoors which was nice as you see the sky and a bit of the city skyline. In the men’s area the steam rooms were small and not very impressive but there were 2 saunas that were huge and hot. Unfortunately both saunas’s had TV inside so it was hard to relax with the TV’s blaring. This must be a Japanese thing as I have not experienced TV’s in saunas anywhere else. The great thing about having so many different pools with various temperature is that you can choose what you like, stay as long as you like and then cool down in one of the cold pools. Overall the spa floor was quite good and provided lots of hot and cold options. There is a separate floor called the Stone Sauna section which you access via the entry to the spa area. Even if you are a hotel guest you have to pay 3800 yen to buy a separate outfit for the Stone Sauna experience which is coed. You get 3000 back when you return your outfit. I did the stone sauna experience which was themed by country. There was a Russian sauna. Korean Sauna, Israeli Salt Sauna, Turkish sauna which was strangely not heated, etc etc. Of all of the sauna rooms, there was only one that was really hot at 60 degrees but this one had a TV in it while the others were quiet which smoothing music.. The other sauna rooms were warn but not really hot. Overall the Stone Saunas were more like fancy themed chill zones. While I did not partake there were a few restaurants, a gym and games room so you really could bring the entire family and have plenty to do! If you like onsens then this is a good city option as it offers much more than your average onsen but in an urban setting.