Great choice — Sri Lanka is one of the world’s strongest destinations for sustainable wellness travel (authentic Ayurveda, nature-based retreats, small eco-resorts). Below are top places to consider, with what makes each special and why they’re good for a sustainable wellness holiday.

1. Sen Wellness Sanctuary — Rekawa / Tangalle (south coast)

• What it is: small boutique eco‑Ayurveda and yoga sanctuary set between a lagoon and turtle‑nesting beach.
• Why sustainable: low‑impact, handcrafted cabanas, protected mangrove setting, local sourcing and conservation work (sea turtle habitat).
• Best for: authentic Ayurveda programs, nature immersion, small-group or solo restorative retreats. (senwellnesssanctuary.com)

2. Amuna Holistic Ayurveda Retreat — Dambulla / Cultural Triangle

• What it is: a purpose-built Ayurvedic centre in a quiet, rural setting offering Panchakarma, personalised Ayurvedic treatment plans, yoga and mindful cuisine.
• Why sustainable: architecture and programs emphasize traditional Sri Lankan living, locally sourced food and an on‑site Ayurveda pharmacy.
• Best for: medically supervised Panchakarma/detox, deeper Ayurvedic therapies and longer stays. (amuna.lk)

3. Santani Wellness Resort — Kandy / Hill country

• What it is: established, award‑winning wellness resort in misty hill country with focused Ayurveda, fitness, yoga and nature trails.
• Why sustainable: architecture designed for natural ventilation (reducing AC use), strong focus on regenerative design and minimalism, large estate set for conservation.
• Best for: active wellness blends (exercise + Ayurveda), cool‑climate relaxation, architecture/design lovers. (wallpaper.com)

4. Tara Ayurveda (TARA Green Resort) — near Marawila / Chilaw or western lowlands (confirm location with provider)

• What it is: a long‑running Ayurvedic resort with licensed Ayurvedic doctors, treatment hospital (Sottisala) and herb gardens.
• Why sustainable: on‑site herb gardens supplying medicines/food, emphasis on traditional therapies and sourcing.
• Best for: authentic clinic-level Ayurveda with comfortable eco‑conscious accommodation. (taraayurveda.lk)

5. Tamarind Tree / Tamarind Ayurveda Resort (Negombo or west coast properties)

• What it is: Ayurvedic resorts combining treatments, organic/local herbs and Ayurvedic culinary principles.
• Why sustainable: focus on organic herbs, plastic‑reduction/eco‑packaging, sustainable food sourcing and garden-to-plate practices.
• Best for: short Ayurveda programmes close to international gateways; good for travelers wanting convenience + eco practices. (ayurveda.tamarindresort.com)

Quick tips for choosing a sustainable wellness holiday in Sri Lanka

• Look for resident Ayurvedic doctors (BAMS) and licensed therapists when booking Panchakarma or medical Ayurveda. (amuna.lk)
• Prefer small boutique centres or resorts with clear conservation projects (mangrove/turtle protection, herb gardens, waste reduction). (senwellnesssanctuary.com)
• Ask about food sourcing (local/organic), plastic policies, energy use (natural ventilation, solar), and community benefits (local hires, training). (ayurveda.tamarindresort.com)
• Best seasons: generally Dec–Mar for the southwest/south coast and May–Sep for the east coast; hill country (Kandy) is pleasant year‑round but cooler. (If you want specific timing for a region or flight logistics from the U.S., I can check dates and current conditions.)

If you’d like, I can:

• Narrow options by region (beach vs hill country vs Cultural Triangle), budget, or program length; or
• Check availability, verified sustainability certifications, or the latest guest reviews for any of these centres.