Great choice — Sri Lanka is compact but hugely diverse for nature lovers. Below are the must-visit natural places, why they’re special, best seasons/what to do, and quick practical tips.

1. Yala National Park (leopards, varied wildlife)

• Why go: One of the best places in the country to see wild leopards, plus elephants, crocodiles and many bird species. Best for classic jeep safaris. (theguardian.com)
• Best time: Dry season / peak safari months (roughly February–June) for highest wildlife visibility. (yalalk.com)
• Tip: Book an early-morning or late-afternoon safari with a licensed operator; parts of the park can be closed or limited during monsoon/maintenance periods, so check ahead.

2. Udawalawe National Park & Elephant Transit Home (elephant-focused)

• Why go: Reliable elephant sightings (large herds) and a nearby Elephant Transit Home where orphaned calves are cared for — great for seeing elephants behaving naturally. (cntraveler.com)
• Best time: Accessible year-round; dry months (May–September) often concentrate wildlife around water. Morning/late-afternoon safaris are best. (udawalawerides.com)
• Tip: Combine a park safari with a visit to the Elephant Transit Home for an ethical, educational experience.

3. Sinharaja Forest Reserve (primary rainforest, biodiversity hotspot)

• Why go: Sri Lanka’s last viable area of primary tropical rainforest — extremely high endemism of plants and animals; a UNESCO Biosphere/World Heritage site. Excellent for birdwatching, butterflies and lowland rainforest treks. (en.Wikipedia.org)
• Best time: Generally drier months (outside the heaviest rains) are easier for trekking; local guides recommended for trails and spotting endemics.
• Tip: Wear waterproof footwear, expect muddy trails; use a knowledgeable guide for bird/endemic-spotting.

4. Horton Plains National Park — World’s End & cloud forest

• Why go: Dramatic plateaus and the famous “World’s End” cliff-drop view; highland cloud-forest ecosystem with unique grasses, montane flora and birdlife. A short, scenic hike (2–3 hours typical). (en.Wikipedia.org)
• Best time: Early morning (start at sunrise) for clear views and cooler hiking conditions.
• Tip: Park is at high elevation—bring warm layers and sun protection; trails can be busy, so go early.

5. Knuckles Mountain Range (remote hikes, endemic flora)

• Why go: Rugged, less-touristed highland range with superb trekking, endemic plants and panoramic valley views — great for multi-day hikes and camping. (thetimes.co.uk)
• Best time: Dry-season windows (generally December–April in the hill country), but check local forecasts.
• Tip: Hire a local guide for route-finding and access to remote villages.

6. Ella & the Hill Country (tea slopes, scenic train, waterfalls)

• Why go: Iconic train journey from Kandy to Ella, misty tea plantations, short hikes (Little Adam’s Peak, Nine Arch Bridge) and waterfall swims — great combination of landscapes and relaxation. (elpais.com)
• Best time: December–March gives clearer skies in the hill country.
• Tip: Book train tickets in advance for the scenic Kandy–Ella route; plan some easy hikes for the best views.

7. Wilpattu National Park (villus, quieter safari alternative)

• Why go: Sri Lanka’s largest national park with seasonal lakes (“villus”) that attract wildlife — quieter and more remote than Yala. Good for birding and large mammals. (kesharasafari.com)
• Best time: Dry season (February–October) when villus are accessible.

8. Minneriya & Kaudulla (elephant gatherings / “The Gathering”)

• Why go: Seasonal mass gatherings of hundreds of Asian elephants at Minneriya (and Kaudulla), among the world’s most spectacular elephant concentrations. Peak months are typically in and around August–September (varies by year). (thetimes.co.uk)
• Tip: Book a jeep safari that times with late afternoon when elephants often concentrate around water.

9. Bundala National Park (migratory and wetland birds)

• Why go: Important Ramsar wetland and great for birdwatching — migratory waterbirds and shorebirds gather here seasonally. (yalalk.com)
• Best time: December–April for many migratory species.

10. Turtle-watching & whale/dolphin hotspots (Mirissa, Rekawa, Kosgoda, Trincomalee/Arugam Bay)

• Why go: Sea turtle nesting and hatchlings (beaches like Rekawa, Kosgoda, and Mirissa); Mirissa and Trincomalee are also known for whale and dolphin tours (seasonal — blue whales often sighted December–April in the south). (thetimes.co.uk)
• Tip: Choose reputable, licensed operators who follow responsible wildlife-viewing guidelines (no chasing, maintain distance).

Quick practical tips for nature travel in Sri Lanka

• Pick regions by season: Sri Lanka has two main monsoon systems — the island’s weather varies by coast and elevation, so plan destinations by month to avoid monsoon closures or heavy rains. (thetimes.co.uk)
• Guided experiences: For safaris, rainforest treks and mountain routes, local licensed guides improve safety, wildlife sightings and conservation-minded behavior.
• Respect wildlife: Stay in vehicles during safaris, don’t feed animals, keep noise and litter to a minimum.
• Permits & park rules: National parks have entrance fees, vehicle/guide rules and occasional block closures for maintenance — check current park websites or a trusted tour operator before travel. (yalalk.com)

If you’d like, I can:

• Build a suggested 7–12 day nature-focused itinerary across these highlights (including travel times), or
• Tailor recommendations to a specific month you plan to travel so you hit the right regions for weather and wildlife.

Which would you prefer?