UBER has long been known as the cheaper alternative to taxi service to get to the Luis Muñoz Rivera Airport (SJU) but, starting tomorrow,
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SJU airport now allows UBER pickups for arrivals
You might find that UBER takes longer than a taxi to pick up at the airport. I have seen it take as long as 20 minutes to wait for an available UBER. My advice, if the wait is too long for you, consider taking a taxi. The taxi stand is directly outside the baggage area of terminal B, and also just to the right of the JETBLUE terminal (terminal A). Uber is typically about $12 to $18, while taxi fare is fixed and to Coqui del Mar Guest House is about $22 (depends on luggage).
To the airport, UBER is definitely the cheapest and easiest way to get to the SJU airport, and is typically about $8 to $10 from Coqui del Mar.