Here are widely regarded private-luxury options across Sri Lanka, organized by region with a short note on what makes each especially private or exclusive, and a practical tip for booking. I’ve cited reputable travel or hotel sources so you can check details and availability.

South coast (beaches & cliffs)

• Amanwella (Tangalle / south coast) — small ultra‑luxury resort with a limited number of pool suites and private garden/pool suites tucked into cliffside and garden settings; extremely quiet, adult‑oriented vibe. Good for couples who want private pool terraces right by the sea. (nearfarmag.com)
• Cape Weligama (Weligama) — cliff‑top resort with standalone pool villas and multi‑bedroom private villas that can be booked for families or groups; villas have private pools, butler service and independent dining/terrace spaces. Excellent for those wanting full villa privacy plus resort facilities. (thehotelscout.com)
• Red Cliffs / Jayewardene House (Mirissa / “House on the Red Cliffs”) — architecturally notable pavilion‑style private house/villa on cliffs above Mirissa; can be booked as a very private whole‑house rental. (Unique pick for architecture lovers who want total privacy.) (en.wikipedia.org)

Hill country (tea country & cool climate)

• Ceylon Tea Trails (Trelawny / Hatton, central highlands) — collection of restored planters’ bungalows; you can book individual bungalows or reserve the entire property for exclusive use. Historic, secluded bungalows with private living spaces and butler service — ideal for a private country retreat. (brandradar.org)
• Norwood / Norwood Bungalow category at Ceylon Tea Trails (example of private‑bungalow experience) — private verandahs and dedicated staff for each bungalow; excellent privacy in cooler hill country landscapes. (honeymoonguidesrilanka.com)

Cultural triangle / countryside

• Uga Ulagalla (Anuradhapura / Cultural Triangle) — heritage manor converted into individual pool villas set across a large estate; each villa is free‑standing with private pool and secluded outdoor areas, giving a “private house” feel inside the countryside. Great if you want privacy near Sigiriya/Polonnaruwa. (honeymoonguidesrilanka.com)

Boutique‑villa choices (small property, very private)

• Kahanda Kanda (near Galle) — small boutique property of standalone suites/villas with private decks and intimate common areas; renowned for design, seclusion and personalized service. Good for couples wanting a private, low‑key luxury stay near Galle. (brandradar.org)
• The Kandy House (Kandy) — a restored colonial manor set in private gardens with villa‑style suites; intimate, heritage‑villa experience with very few rooms so the atmosphere is quiet and private. (thetimes.co.uk)

Other private‑villa brands & bespoke options

• Small independent beachfront villas (Ani Villas, Saman Villas, private beachfront estates) — many one‑to‑three‑villa estates on the south and southwest coast offer private pools, chefs and butlers for fully private stays. Good for families or groups wanting an entire beachfront home. (hidmc.com)

Booking & planning tips

• Decide region first (south coast for beaches, central highlands for cool tea‑country, cultural triangle for history) — privacy availability varies strongly by region.
• If you require guaranteed exclusivity (whole‑house privatisation), confirm with the property whether “private villa” means standalone accommodation versus a villa within a resort; request written confirmation if you need the whole property or private staff. (brandradar.org)
• Peak seasons: south coast high season is roughly November–April; hill country is pleasant year‑round but also busy during local holidays. Book well in advance for villas or whole‑property buyouts.
• Ask about included staff (butler/chef), cancellation policy, transport from main airports (Colombo) and whether the villa has a private entrance/parking if total seclusion matters.

If you want, I can:

• Shortlist by exact travel dates and desired region (I’ll check live availability/rates), or
• Pull contact/booking links and current sample rates for 3–5 specific villas you like.

Which region or type of privacy (private pool villa vs whole‑house buyout vs tiny boutique manor) do you prefer?