Here are well-known Colombo hotels that offer banquet halls and meeting facilities (with typical capacities / notes and sources you can contact for rates & availability):

1. Shangri‑La, Colombo — multiple ballrooms (Shangri‑La Ballroom up to ~2,500–3,000 reception / 1,440 banquet; Lotus and Spice ballrooms and smaller meeting rooms). Great for large conferences and gala dinners. (Shangri-La.com)

2. Cinnamon Grand Colombo — several large ballrooms and meeting rooms suitable for weddings, conferences and banquets (hotel is a major events venue in Colombo; contact for specific room capacities and layouts). (Shangri-La.com)

3. Cinnamon Lakeside Colombo — large banquet and ballroom spaces, well suited for corporate events and weddings (ballrooms and meeting suites; confirm capacities with events team). (tajhotels.com)

4. Taj Samudra, Colombo — multiple halls and landscaped lawns; venues for small meetings up to very large events (lawns that can host up to ~2,000, ballrooms and indoor halls up to several hundred). (tajhotels.com)

5. Hilton Colombo (connected to World Trade Centre) — pillar‑free Grand Ballroom (banquet capacity several hundred; ballroom options up to ~700–900 for large events) plus smaller meeting rooms. (Hilton.com)

6. Hilton Colombo Residences — large Union Ballroom (theatre up to ~1,100; banquet capacities listed per room) and multiple flexible meeting rooms. Good for conferences and gala dinners. (Hilton.com)

7. Jetwing Colombo Seven — contemporary meeting spaces (Barnes — banquet ~120 / cocktail ~150; Kynsey — smaller boardroom-style space ~50). Suited to corporate meetings and medium-sized events. (jetwinghotels.com)

8. Galle Face Hotel — historic seafront hotel with banquet/function rooms and lawns used for weddings and events (contact hotel for current capacities and set‑ups). (tajhotels.com)

Practical next steps

• If you tell me your expected guest count, preferred date(s), and whether you need AV, breakout rooms, catering style (buffet / plated), or outdoor space, I can narrow this to the best 2–3 hotels and pull current capacity charts or request availability/quotes.
• For immediate booking or detailed floorplans/pricing, contact the hotel events team directly (hotel websites linked in the cited pages above have “Meetings & Events” / enquiry forms).

Would you like me to narrow these by guest count or date and fetch current availability and quotes?