Michael McComish is poised for a return to Ravenhill
Connacht back row Michael McComish and Worcester Warriors prop Callum Black will join Ulster in the summer.
Former Ulster development player McComish had spells with Rotherham and Otley before joining Connacht in 2009.
Black was born in the USA but is Irish qualified and has represented Ireland at U18, U19 and U21 levels.
Meawnhile, Connacht have signed Ulster back-row Thomas Anderson in a two-year deal while prop Brett Anderson has agreed a contract extension.
Black, who was raised in England, is Irish-qualified through his paternal grandfather, who was originally from Belfast.
The 25-year-old joined the Worcester Academy straight from Hartpury College and burst onto the senior scene towards the end of the 2008-09 season.
He has made 50 appearances in the front row for the club and has had loan spells at Otley and Plymouth.
"I'm at the stage in my career where I'm looking to really push on and I'm really looking forward to playing in the Magners League and Heineken Cup," added Black.
"My goal is to establish myself in the Ulster team and then try to force my way into the Ireland set-up.
"I've watched Ulster this season and been very impressed with how the team is developing and I'm looking forward to being part of that."
McComish attended Campbell College and went on to play a key role in the Ballymena team which won the All-Ireland Division One title in 2004.
The 27-year-old has played for Ireland at U21 level and has also represented the Ireland sevens side.