Hawaii Republicans will have a full field for their inaugural presidential caucuses on March 13.

The state GOP announced on Friday that former U.S. Sen. Rick Santorum had registered for the ballot. Santorum joins former Massachusetts Gov. Mitt Romney, former U.S. House Speaker Newt Gingrich, and U.S. Rep. Ron Paul.

“We are pleased that all of the front running Republican presidential candidates are now on the ballot,” David Chang, the party’s chairman, said in a statement. “The Hawaii Republican Caucus gives voters a real choice and a real voice in the presidential race.”