Maui
The ocean was beautiful and the environment was very nice, but I felt that it was tough since almost no one on Maui speaks Japanese, so you need to have at least a basic level of English for everyday conversations.
海はきれいでとても環境はよかったのですが、マウイ島はほとんど日本語が通じないので日常会話程度の英語ができないときびしいと感じました。