Alturia

I have usedSIM cards from both OneSimCard (http://www.onesimcard.com/) and Telestial (http://www.telestial.com/) and both worked well for both voice and data when traveling.

Both companies list the countries they work in. Telestial covers a few more than OneSimCard. I purchased Telestial because it works in Bermuda and OneSimCard doesn't.

When we did this cruise with Windstar last January, they arranged a bus from the hotel in Panama City to Colon. If you are not staying at the hotel Windstar uses (forgot the name of it) you could probably book the bus and meet it at that hotel. In any case, I would call Windstar and ask them about transportation from Panama City to Colon.