Phuket isn't a major hiking destination, but a handful of genuine trails exist beyond the standard waterfall walk.
Khao Phra Thaeo National Park trails
The park's rainforest trails, leading to the Bang Pae and Ton Sai waterfalls (see our national parks guide), offer the island's most substantial forest walking, generally short but genuinely forested rather than a paved path.
Coastal and viewpoint walks
Shorter walking routes lead to some of the island's viewpoints and quieter beaches (Laem Singh and Freedom Beach both involve a walk down from road access) — less "hiking" in the dedicated-trail sense, more a walking component of getting somewhere else.
Setting expectations
None of this compares to hiking destinations elsewhere in Thailand or the region — trails here are short, humid, and best treated as a half-day addition to a broader day out rather than a standalone hiking trip.
Practical notes
Humidity and heat make even short trails more demanding than the distance suggests — water, sun protection and starting early are worth treating as standard rather than optional.