How long does it take to fill a Hot Tub?

The majority of portable Hot tubs are filled with a hose pipe. The time it takes to fill it with water will depend on how much water needs to be put into the spa, what size of pipe you are using and your water pressure. If you are in the UK, have reasonable water pressure, and are using a standard 3/4″ UK hose and filling a 300 gallon spa, I would expect this to take between 1.5 and 2 hours approximately.