Jack McGrath, Craig Gilroy, Marcus Rea and Greg Jones have all signed one-year contract extensions with Ulster.
Prop McGrath, who recently returned from a long-term injury, made the move to Ulster in 2019 and has 56 caps for Ireland, including success in the 2014, 2015 and 2018 Six Nations, while he appeared in all three Tests on the 2017 Lions tour of New Zealand.
Craig Gilroy recently made his 200th appearance for the province against Ospreys.
The prolific try-scoring winger has scored 68 tries so far in his Ulster career, closing in on the province record of 76 currently held by Andrew Trimble.
24-year-old back-row Marcus Rea, an Ulster academy graduate, made a try-scoring contribution on his senior debut versus Leinster in April 2019.
The Ballymena man has gone on to impress with his breakdown work in his 12 appearances so far.
Jones joined the academy from UCD in 2017, and made his senior Ulster debut against Benetton in the same year.
He has made a notable impression, including his try-scoring performance against Ulster's victory over Leinster at the RDS.
Head coach Dan McFarland, whose side host Scarlets in the URC tomorrow, said: "It is encouraging to have secured the services of a further four of our current playing squad, with all set to play an important role in our plans for next season.
"Jack and Craig bring extensive experience and expertise, while Marcus and Greg have really grown into their roles within the club. I look forward to what they can achieve individually and collectively in the time ahead."
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