The Hakuba water jump is a great place to hone your big air skills out of the snow season. Professional athletes have been using water jumps since 1978 for their off season training and is now an integral part of aerial skiing. Coaches will train their athletes on water jumps prior to performing a trick on the snow due to less impact on the water landing. It still can be quite brutal especially off the big jump so helmets and life vests are compulsory and wrist, knee and elbow guards are recommended. You can rent all of the equipment required on site. As there are a number of different levels of jumps it is a great place to take the children and instruction is available.
The entrance of the jump is at the north west end of Aokiko Lake
Open 25th May until the 20th October
There is more info on their website here.