Lodges everywhere are flying green flags. So how do you know who's for real? Boulder, Colorado–based Sustainable Travel International (STI) just launched a first-of-its-kind certification program in February. By year's end, the group hopes to post more than 100 ratings at sustainabletravelinternational.org. Until then, STI's Brian Mullis gives us five lodges that do it right.

Hotel Punta Islita, Costa Rica: Set in the forest of Guanacaste province, this base for hiking and kayaking has helped finance a school and a composting station. Doubles, $180; hotelpuntaislita.com

Yachana Lodge, Ecuador: Learn about the medicinal powers of local plants at this boat-accessed Amazon lodge, which funds environmental programs in the Napo River region. Three days, $405 per person; yachana.com

Damaraland Camp, Namibia: Desert elephants and oryx roam the Torra Conservancy, which is supported by a cluster of luxury safari tents near the Huab River Valley. $179 per person; wilderness-safaris.com

Daintree Eco Lodge & Spa, Australia: Aboriginal-inspired treatments like the Corroboree dance massage dominate the spa menu at this rainforest retreat. Doubles from $550; daintree-ecolodge.com.au

El Nido Resorts, Philippines: Jackfish mill about the coves of Bacuit Bay, where resort staff teach guests about conservation and patrol the waters for illegal fishing. From $200 per person; elnidoresorts.com