San Juan is in Puerto Rico - just making sure you are flying into the right place! Anyway, you can only get the Celebrity transfer if you are flying in the day of the cruise [always risky] between certain hours.
Firstly do you mean San Jose, Costa Rica or San Juan, Puerto Rico? I have had a stretch limo from the airport to the dock in San Juan and as it was a long time ago I can only remember that it was not expensive. You can avoid a lot of waiting around by getting a taxi to the ship but it will cost. You can play both ends against the middle by keeping your transit voucher, if you have one, and finding out the taxi costs when you arrive. You should always establish the cost before taking a taxi anywhere and if you take the taxi please make sure that the transit coach is not being held up because they don't know you have taken a taxi. Sorry that's a long winded reply to a fairly simple question but I hope it helps....Nei.