Apple Watch Series 3

Please see Apple Watch - Carriers - Apple and note there is no indication that Costa Rican networks are supporting the cellular versions of Apple Watch yet. That means you can only link an Apple Watch by pairing with a compatible iPhone. The US cellular version is compatible with any iPhone, but it will behave the same as the non cellular version. If your iPhone's network provider doesn't support Apple Watch you may as well just buy the GPS-only version without cellular, and save some $$$