The 21-year-old, who is comfortable playing in any position on the left-hand side of the pitch, will link up with the Seasiders ahead of the 2024/25 Northern Premier League campaign.
Collins, who has been on Boro's books since the Under-11 age group, possesses excellent speed and athleticism.
In the 2023/24 Premier League 2 season, Collins made eight appearances for Middlesbrough's youngsters as they finished 11th in England's top youth league.
On joining the club, Collins said: "I'm delighted to get this deal done and start playing men's football and get a good taste of it.
"I'm ready for the challenge and with the team we've got I think we can do really well this season and go far.
"I've spoken to some of the lads and everything they said about the club was positive so it was an easy decision for me really.
"I can't wait for the season to start and play in front of the fans."
Speaking to whitbytownfc.com Whitby Town manager, Nathan Haslam, said: "Sam is a left-sided player who has predominantly played left-back at Middlesbrough. He's equally as comfortable further up the field as well.
"He's very quick, he's an athlete, and he's a great character. He's got the type of profile that we've done really well with in the past with the lads we've had from Middlesbrough."
Photo credit: Middlesbrough Football Club