Oxalis is unquestionably the expert in caving and trekking expeditions, and is the only outfit licensed to conduct tours to Hang Son Doong. Staff are all fluent English-speakers, and trained by world-renowned British cavers Howard and Deb Limbert.

All excursions, from day trips to Tu Lan to four-night/three-day expeditions to the world's largest cave, are meticulously planned and employ local guides and porters, so the wider community benefits. You can discuss trips at Oxalis'riverside Expedition Cafe.

Prebooking Son Doong for the following year is essential and, if possible, booking a few months ahead for expeditions in Tu Lan and Hang En is recommended to avoid disappointment.