1. Ensure you have a current passport

1. You need a visa which can be obtained upon arrival in Nepal

1. Ensure your vaccinations are up to date.

1. Travel insurance - look for an explorer package and in particular kayak cover.

1. Equipment - paddle, helmet, wet suits etc, you can even bring your own boat if you wish. Equipment is available for hire.

See advice on many of the above points from the following websites

US Department of State - Travel State Gov

Foreign & Commonwealth Office Travel