Seinehaven is a waterfront area located near Heenvliet on the island of Voorne-Putten in the Netherlands.

It sits adjacent to Put van Heenvliet, a recreational lake that formed during large-scale sand extraction in the 1970s and 1980s, when material was dredged to support infrastructure development in the Rotterdam region.

The former sand pit has since been redeveloped for recreational use. The Seinehaven also marks the point where the historic Voorne Canal was dammed off near Heenvliet.

A small section of the canal north of the dam remains accessible from the Voedingskanaal Brielse Meer and continues to serve as a marina, making Seinehaven a practical access point for boaters exploring this corner of Voorne-Putten.