This is a relatively new option in Nicaragua, a direct response to travelers in Granada  and León  who would rather not negotiate taxi fees or muck around with the chicken buses. You’ll board a new minivan filled with other tourists willing to spend $15–20 to be whisked between the pueblos, beach towns, and ferry docks. Most offer airport service as well.
Start with Nica Express (tel. 505/2552-8461, info [at] nica-adventures [dot] com, www.nica-adventures.com ); they maintain a set schedule of departures throughout the country.
Paxeos (tel. 505/2552-8291 or 505/8465-1090, www.paxeos.com ) is another reliable shuttle service, based in Granada, specializing in personal airport pickups at any time of night (and they have an online booking service).
You can also check tour operators, especially Vapues Tours and Tierra Tours, who offer shuttles and airport transfers.