Short answer — use a mix of big OTAs for choice and price-checking, plus direct booking (or Airbnb) for villas/unique places and to get perks. Good places to search and book:

• Booking.com — widest selection in Sri Lanka and strong flexible-cancellation/filters for hotels, guesthouses and resorts. (booking.com)
• Agoda — often shows competitive rates in Asia (useful for many Sri Lanka properties), but double-check confirmations with the hotel (see tips below). (en.wikipedia.org)
• Airbnb — best for private villas, houses and longer stays (many high-rated villas on the south coast and cultural triangle). (airbnb.fr)
• Expedia (and Orbitz/Hotels.com) — good if you want flight+hotel packages or loyalty/credit benefits. (expedia.com)
• The hotel’s official website / call the property — often gives the best direct perks (price-match, flexible policies, loyalty points and easier special requests). Major travel outlets recommend checking/booking direct when possible. (travel.usnews.com)

Practical tips for booking in Sri Lanka

• Cross-check important reservations: after booking on an OTA, email/WhatsApp or call the hotel to confirm they received the booking and the reservation number — travelers and guidebooks in Sri Lanka recommend this as a safeguard. (anyflip.com)
• Consider “pay at property” or flexible-cancellation rooms if you’re worried about inventory problems; still confirm directly with the hotel a few days before arrival. (anyflip.com)
• For villas/long stays, Airbnb or contacting local guesthouses directly can get you better weekly/monthly rates. (airbnb.fr)
• If you want help or have a problem on arrival, Sri Lanka’s official tourism site and SLTDA have tourist information/complaint contacts. (srilanka.travel)

How to choose:

• Best for selection & last‑minute: Booking.com. (booking.com)
• Best for Asia-focused deals (compare against others): Agoda — but confirm directly. (en.wikipedia.org)
• Best for whole-house villas and unique stays: Airbnb. (airbnb.fr)
• Best for bundling flights + hotels: Expedia family of sites. (expedia.com)
• Best practice: compare prices across 2–3 sites, then check the hotel’s own site and call/WhatsApp them to confirm and (sometimes) negotiate a direct rate or add-ons. (travel.usnews.com)

If you want, tell me:

• your travel dates, budget and which part(s) of Sri Lanka you’ll visit (Colombo, Cultural Triangle, Hill Country, South/East coast) and I can search and compare a few specific hotel options and ordering-by-priority (best value / best location / best luxury) for those dates.