Boney, 21, has had loan spells at Nantwich Town and Solihull Moors in recent seasons, and has made six first-team appearances for the Tangerines.
South Shields joint manager Lee Picton said: “We are delighted to bring Myles into the club.
“Myles has been a full-time professional at Blackpool for the last four years and brings with him all the credentials required to provide genuine competition for the number one shirt.
“I’ve been massively impressed with him as a young man during the many conversations we’ve had over the last couple of weeks.
“He is young, hungry and determined to make an impact at the club, and I greatly look forward to seeing him, Liam and Ross push each other and improve each other over the coming months.
“We are extremely fortunate to now have three very high-quality senior goalkeepers at the club.”
Keep up-to-date with our exclusive email newsletters.
Subscribe