This is a relatively new option in Nicaragua, a direct response to travelers in Granada [1] and León [2] 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 [3]); they maintain a set schedule of departures throughout the country.
Paxeos (tel. 505/2552-8291 or 505/8465-1090, www.paxeos.com [4]) 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).
Adelante Express (tel. 505/8850-6070, www.adelanteexpress.com [5]) is based in San Juan del Sur [6] and also offers full service shuttles and transport; 24-hour advance reservation required.
You can also check tour operators, especially Vapues Tours and Tierra Tours, who offer shuttles and airport transfers.
Links:
[1] http://www.moon.com/destinations/nicaragua/granada
[2] http://www.moon.com/destinations/nicaragua/northwest-coast/leon
[3] http://www.nica-adventures.com
[4] http://www.paxeos.com
[5] http://www.adelanteexpress.com
[6] http://www.moon.com/destinations/nicaragua/southwest-coast