Both sports were due to go ahead in the villages of Mulinu’u and Vaiusu, but they will now take place in Mulifanua.
The new venue has hosted both va'a and sailing competitions before, during the 2007 South Pacific Games.
The change was made "after several obstacles were encountered" while planning for the use of both Vaiusu Bay and Mulinu'u peninsula.
"The Sports Committee in collaboration with the Samoa Outrigger Canoe Association believe that the use of Muifanua as a competition venue is very ideal for va'a as the bay provides flat water, with pristine conditions and great views of Samoa," the Games organisers said in a post on Facebook.
"The Samoa 2019 Pacific Games is excited to return va'a and sailing to Mulifanua, the home of the sport during the 2007 South Pacific Games, and expects to produce exciting competition while showcasing the beauty of Samoa."
The Games are set to go ahead from July 7 to 20, featuring around 4,000 athletes.