go swimming [go to swim] in the sea
海に泳ぎに行く. - 研究社 新英和中辞典
to act as middlemen―act as go-between―go between the two parties―mediate between the two parties―negotiate between the two parties
仲人になる - 斎藤和英大辞典
to go to the bath
風呂へ行く
http://ejje.weblio.jp/sentence/content/go+to+the