Inspect the old caulk around the tub surround, looking for breaks or missing portions.
Apply a caulk remover to the old caulk. Let it sit for the recommended amount of time indicated on the back of the packaging. Scrape the old caulk from the tub surround using a razor blade.
Cut the end off a tube of caulk at a 45 degree angle. Place the caulk into a caulk gun. Press the trigger of the caulk gun to get the caulk flowing.
Press the end of the caulk tube to the tub surround and apply a 1/4-inch bead of caulk along the surround joint.
Wet your finger and press the caulk into the joint to make it smooth. Wipe away messy caulk using a wet rag.