The towering 27-year-old set to compete with Vito Mannone for the number one jersey.
Pantilimon is looking forward to the challenge and believes a bright future lies ahead on Wearside.
He told Dolce Sport: "I can tell you that it was a very quick transfer.
"I had discussions with the manager (Gus Poyet) and I was convinced immediately by his way of seeing things, as he presented me with all of his future plans concerning the team.
"I am convinced that I will enjoy many good things here.
"Meeting an ambitious man with the will to be successful is very important to me.
"The team may not be on the same level as Manchester City, but it is a team set to enjoy nice achievements."
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