The central defender will add some experience and quality to the United backline.
The 34-year old Dundonian began his professional football career with Dundee in 2005 before making his senior debut on loan at Montrose.
After leaving Dens Park he enjoyed a spell with Lochee United between 2007 and 2012.
The defender helped the Bluebells win the East of Scotland Junior Cup, the Fife & Tayside Cup and the Super League in 2008.
Hay played in 62 matches for Brechin City between 2012 and 2014 as the Hedgemen reached the Scottish League One play-offs and he proved to be an influential club captain around Glebe Park.
He also went on to play for Formartine United, Arbroath and Cowdenbeath and he has most recently spent time on the books of Broughty Athletic.
Leaving the club, though, is Matthew Hutchison.
Hutchison made 24 appearances last season and won the club’s goal of the season award for his last-minute equaliser at Haddington Athletic in November.
Midfielder Jason Penman, versatile defender Jack Rollo and goalkeeper Kyle Moran have been placed on the transfer list as Raeside looks to create his own squad ahead of next season.
Kieran Lindsay and Harris Haleef are also leaving The Clayton Caravan Park Recreation Ground this summer at the end of their current contracts.