Preheat oven to 350 degrees F (175 degrees C). Line a roasting pan with aluminum foil.
Set ham into the prepared roasting pan and pierce several times with a fork.
Stir brown sugar, peach preserves, and mustard together in a bowl; spread over the ham. Cover the ham with a sheet of aluminum foil.
Roast ham in preheated oven, basting regularly, for 90 minutes. Remove the aluminum foil cover and continue baking until hot in the center, 30 to 45 minutes. An instant-read thermometer inserted into the center should read 140 degrees F (60 degrees C).