Most 10-day itineraries online are fantasies. Here's one that actually works — where you spend more time seeing things than sitting in traffic.
Day 1–2: Arrive Colombo, drive to Negombo or straight to Kandy (2.5 hours from airport). Stay in Kandy, see the Temple of the Tooth, walk the lake, eat at the Devonia Guesthouse for proper rice and curry. Day 3: Drive to Sigiriya (2.5 hours). Climb Pidurangala in the late afternoon, sleep at a hotel with a view of the rock. Day 4: Sigiriya morning, then drive to Nuwara Eliya (3 hours) via Ramboda. Stop at a tea factory. Day 5: Drive to Ella (2 hours from Nuwara Eliya). Do Little Adam's Peak for sunset. Day 6: Morning hike to Ella Rock, afternoon train to Kandy? No — don't. You've already come this way. Stay in Ella. Do Nine Arches Bridge early. Day 7: Drive to Udawalawe (1.5 hours) for afternoon safari, then continue to the south coast — Mirissa or Weligama (another 2 hours). Day 8–9: Beach time. Surf or whale watch or just sit and do nothing. Day 10: Drive back to Colombo (3 hours from Galle area) for your flight out.
This route skips the east coast entirely (wrong season for most people) and avoids the Colombo city stop (you'll pass through). It gives you three nights in the hill country, two safari options, and solid beach time. The longest drive is 3 hours. You won't hate yourself by day 7.
The common mistake is trying to add Anuradhapura, Trincomalee, Arugam Bay, and Jaffna into a 10-day trip. You can't. You'll spend half your trip unpacking and repacking your suitcase. This route is honest about what fits.