Super Nintendo World - which cost about $0.5bn ($0.36bn) to build - was meant to open last summer but was delayed by the coronavirus pandemic.
Initially only Japanese visitors can go amid international travel bans.
For Nintendo, it represents part of a move from games firm to entertainment company.
At first the park will take half of the visitors it can accommodate to comply with social-distancing measures. Visitors will need to wear masks in most areas.
