Fuel and energy: the biggest impact

A liveaboard burns 200–500 litres of diesel a day. Look for: solar panels (reduces generator use), modern engines (lower emissions per nm), routes that minimize sailing time. Newer boats (built post-2015) typically have ~40% better fuel economy.

Plastic-free or plastic-light?

Reusable water bottles for guests (not a single bottle of bottled water on board): essential. Refillable shampoo dispensers: good. Plastic straws / plastic cutlery / individual plastic snack packets: red flags. Ask the operator directly — most have a sustainability page on their site.

Reef-safe diving practices

Briefings that emphasise no-touch, no-kneeling, no-fin-on-coral. Mooring buoys (not anchoring on reef). Crew that corrects bad behaviour. Operators that ban gloves on coral reefs. If a boat doesn't talk about this on day 1, they probably don't enforce it.

Marine park fees: where the money goes

Fees in Galápagos, Komodo, Maldives, Egypt fund park rangers and reef protection. Ask the operator if there are any additional voluntary contributions to local conservation NGOs. Many top-tier boats donate per-guest amounts to projects like Manta Trust, MarAlliance, Reef Check.

Certifications worth checking

Green Fins (UN-backed): real, audited. PADI Eco Center: meaningful for resorts, less so for boats. Anything self-declared (e.g., 'eco-platinum award'): ignore. Travelife / Earth Check: rare on liveaboards but legitimate.

Local economy and crew welfare

Crew should be majority local nationals (not all expats). Fair wages and tip distribution policies should be transparent. Sourcing food from local fishermen and markets (not imported supplies) supports the community where you're diving.