The 31-year-old defender, who can play at centre- or left-back, has moved to Upton Park after struggling to cement a regular place at the Britannia Stadium under Tony Pulis
The 31-year-old, who can play as a centre-back or at left-back, has joined the Upton Park outfit until May 21 and is available for the Hammers' Championship match against Doncaster Rovers on Saturday.
Collins was sent out on loan to Ipswich Town in September but has only featured twice for Stoke since returning to the Britannia Stadium after his spell with the Suffolk club finished.
"West Ham are going well in the league and looking for promotion," Collins told his temporary side's official website.
"They are having a good season so this was a chance for me to come out on loan and get some games in.
"Hopefully I can come down here, get myself into the team and be part of it.
"I went out on loan to Ipswich earlier this season and played 16 games there and I've played a few games for Stoke, but I want to be playing week in, week out if I can."
Stoke are 12/1 with Bet365 to get a 0-0 draw with Chelsea on Saturday.