It was very comfortable inside.. I had fears of being under water but it was very roomy and was a great experience! You will love it and the staff is awesome!

Only about 2 1/2 hrs. They take you on a boat out to the semi - sub. The sub is above water but you go down inside and are underwater with seats and windows! Very enjoyable!

Tengo. Q reservar el paseó en el submarino en Aruba Estoy en un crucero y llego. A Aruba el 17 de julio

Well, on the boat is easy, just like walking anywhere, but to down the sub there are stairs and don't remember the level of difficulty, but you do have to go up and down. The boar ride is a regular boat ride and there are no particular waves and jumping up and down (the sea is mostly calm) - but I suggest you come to the port and talk to them - and they will let you know. There is a nice restaurant where you can seat and enjoy. The tour is actually short so your back and knee should be fine, but then again I remember one tour didn't take people with back problem, so it's better to double check.