Denton last played for West Ham in December’s 5-1 defeat by Manchester City in the League Cup quarter-finals.
She leaves West Ham with the club 11th in the Women’s Super League, one point above Liverpool in the relegation play-off spot.
Denton will reunite with former England Under-23s manager Emma Coates when she joins Bay FC.
“I’m really pleased to welcome Anouk to Bay. She’s someone I have worked with before, so I know exactly what she brings,” Coates said.
“She brings valuable experience at the top level from her time in the WSL, and what’s exciting is that there’s still room for her to grow.”
Based in the San Francisco Bay Area, Bay FC finished 13th of 14 teams in the National Women’s Soccer League last season, registering just four wins in 26 matches.
The 2026 NWSL season starts in March, with Bay FC kicking off their campaign against Denver Summit.
