Goonhilly Downs is a Site of Special Scientific Interest (SSSI) that forms a raised plateau in the central western area of the Lizard peninsula in southern Cornwall, England.

Approached from the Helston direction and half a mile before the Satellite dishes is the former Goonhilly Craft Shop and Tea Room, now converted to a private dwelling.

Goonhilly Downs also serves as a landing point for the SEA-ME-WE 3, the longest submarine cable on Earth.

Nearer to Mullion are other triple SIs including the North Predannack Downs Nature Reserve, owned and managed by the Cornwall Wildlife Trust.

This reserve is prime Cornish heath (Erica vagans) with ponds and willow fen.