"I'm definitely grateful to re-sign with the Dolphins," Thomas said. "I thank all of them for taking care of me, mainly because hopefully I can end my career here.
"It's a long contract and I was definitely looking forward to staying here because I love it down here."
The new deal was reached shortly before the Dolphins were due to pay Thomas a roster bonus. The sides had been talking on and off for a while.
"This will allow him to be a Dolphin for his entire career, and that is important to us," said Dolphins president Eddie Jones. "It's also in accord with our philosophy to reward our top players, and we've been successful in keeping our good players.
"We've got 21 of 22 (starters) this next season under contract and we're always pleased to be able to do that. We have a good football team and we think it's important to keep it together."