The isletas — 365 small islands thrown into the lake when Mombacho collapsed — are best seen from a kayak rather than a motor launch, which is what this outfit does: a couple of hours paddling the channels between them, with herons, kingfishers and the odd howler monkey.
They also run the wider Granada circuit: Mombacho's cloud forest, the Masaya volcano at night, and Laguna de Apoyo.