Great — here are focused, practical romantic beach-getaway options in Sri Lanka, with timing, where to stay, what to do, travel logistics, sample itineraries and budget tips.

Top romantic beach areas (what makes each special)

• Mirissa — classic crescent bay, calm swimming, whale‑watching (best Dec–Apr). Great for sunset dinners and private boat trips. (feelfreetravel.com)
• Unawatuna / Galle / Koggala — pretty bays, historic Galle Fort nearby (easy to combine culture + beach). Best Dec–Mar/Apr. (colomboairporttaxi.info)
• Tangalle (including quieter stretches like Goyambokka) — palm-fringed, low‑crowd beaches and upscale resorts for privacy. (en.Wikipedia.org)
• Weligama / Hiriketiya — surfable bays, chic boutique resorts and surf lessons for couples. (thetimes.co.uk)
• East coast (Trincomalee, Pasikudah, Arugam Bay) — turquoise, shallow bays and surfing (best May–Sep) — ideal if you want quieter beaches outside the southern coast high season. (sunspireholidays.com)
• Kalpitiya — kitesurfing and dolphin watching if you both like active water sports. (thetimes.co.uk)

Best time to go (region matters)

• South & West coasts (Mirissa, Unawatuna, Galle, Tangalle, Weligama): December–March (peak beach/whale‑watching season; calm seas). (sunspireholidays.com)
• East coast (Trincomalee, Passikudah, Arugam Bay): May–September (dry, calm seas for swimming/diving/surfing). (feelfreetravel.com)

Sample romantic stays (types; examples)

• Ultra‑luxury/secluded: private‑villa or high‑end resort near Tangalle or Weligama (e.g., Anantara Peace Haven at Tangalle / villas near Goyambokka). These focus on privacy, spa and bespoke dining. (en.Wikipedia.org)
• Boutique/romantic: small hotels and design resorts in Galle, Unawatuna, Mirissa or Hiriketiya offering intimate dining and ocean views. (thetimes.co.uk)
• Active/casual: surf camps or beach bungalows in Weligama and Arugam Bay if you want a relaxed, sporty vibe. (thetimes.co.uk)

How to get there & between beaches (practical)

• From Colombo (Bandaranaike airport or city) to the south coast: Galle is ~1.5–2.5 hours (expressway/train/bus options); Mirissa is roughly a further ~30–60 minutes beyond Galle — typical car/train times Colombo→Mirissa around 3 hours (varies by route and traffic). Book private transfers for convenience. (geckoroutes.com)
• Trains down the west/south coast are scenic and affordable (Colombo→Galle route ~2–2.5 hrs); expressway buses and taxis are faster but cost more. For island logistics, private car + driver gives the most flexible romantic itinerary. (geckoroutes.com)

Romantic activity ideas

• Private sunset boat or candlelit beach dinner. (feelfreetravel.com)
• Whale/dolphin watching from Mirissa (best Dec–Apr). (feelfreetravel.com)
• Strolls and a sunset at Galle Fort with cocktails and boutique shopping. (geckoroutes.com)
• Couple’s spa, private villa breakfast, and spice-garden or tea‑estate short excursions if you want a day off the beach. (thetimes.co.uk)
• Surf or surf lessons together in Weligama/Hiriketiya or catch waves at Arugam Bay (east coast seasonally). (thetimes.co.uk)

2 sample itineraries (4–6 days)

Option A — South coast, relaxed & romantic (4 nights)

• Day 1: Arrive Colombo → private transfer to Galle/Unawatuna. Sunset walk at Galle Fort, dinner in town.
• Day 2: Beach day Unawatuna; private candlelit dinner on the beach.
• Day 3: Transfer to Mirissa (short drive). Afternoon spa, evening whale‑watching next morning option.
• Day 4: Whale/dolphin trip (early morning) or private boat/seafood lunch; late afternoon sunset drinks.
• Day 5: Back to Colombo or extend to Tangalle for a quieter final stay.

Option B — East coast surf & seclusion (5 nights; best May–Sep)

• Day 1: Arrive Colombo → fly/drive to Trincomalee or drive to Arugam Bay.
• Day 2–3: Relax on shallow turquoise beaches (Pasikudah/Nilaveli) with snorkel/dives.
• Day 4: Day trip for cultural site or lagoon tour; sunset on the beach.
• Day 5: Surf day (Arugam Bay) or leisurely spa and romantic seafood dinner.

Estimated budget ranges (per couple, per night examples)

• Budget boutique/guesthouse: $40–100/night (simple romantic stays).
• Mid‑range boutique/resort: $100–250/night (good amenities, private dinners/spa).
• Luxury/private villa/resort: $300–1000+/night (private pool, fine dining, high privacy).
  (Prices fluctuate by season — peak Dec–Mar higher; book early for holiday periods). (sunspireholidays.com)

Booking & planning tips

• Peak season = December–March on the south/west coast; book resorts, whale‑watching and private transfers well in advance. (sunspireholidays.com)
• If you want both quiet and good weather, consider shoulder months (Nov or Apr) but expect some inter‑monsoon short rains; for truly quieter beaches with good weather pick the east coast in May–Sep. (feelfreetravel.com)
• Choose private transfers for door‑to‑door convenience (especially for couples who want privacy). Trains are scenic but can be crowded. (rome2rio.com)

Safety, health & practical

• Seas can be rough in the wrong season — swim only where lifeguards/flags indicate safe conditions and follow local advice. Best swimming months depend on the coast (see timing above). (colomboairporttaxi.info)
• Standard travel prep: up‑to‑date travel insurance, check visa requirements before travel, routine vaccinations current. (If you want, I can check visa/entry requirements for your nationality.)

If you’d like, I can:

• Build a 4–7 day romantic itinerary tailored to your dates, arrival city and pace (laid‑back vs active).
• Find specific highly rated romantic hotels or private villas (I can pull current availability and prices).

Which would you prefer — a quiet luxury escape (Tangalle/Anantara‑style), a lively combo (Galle + Mirissa), or an active surf/sea adventure (Weligama/Arugam Bay)? I can then make a short day‑by‑day plan and list a few recommended properties with booking links.