Here are the top hotels in Colombo well suited for conferences and business events, with the key event strengths of each and sources you can contact or check for details.

1. Shangri‑La, Colombo — large, modern event complex; ballrooms and meeting rooms that can host very large conferences (reported capacity up to ~2,000), full AV and event-planning services; prime Galle Face/One Galle Face location. (en.wikipedia.org)

2. Hilton Colombo — connected to the World Trade Centre with extensive event space (total event space ~1,373 m², pillar‑free grand ballroom seating up to ~900), multiple meeting rooms and on‑site multilingual planners. Good for mid‑to‑large corporate conferences. (hilton.com)

3. Cinnamon Grand Colombo — long‑established conference hotel with multiple ballrooms and smaller meeting rooms (Oak Room / Atrium / Ivy etc. — largest setups for several hundred to 800+ theatre), experienced events team and central Galle Road location. (cinnamonhotels.com)

4. Cinnamon Lakeside Colombo — lakeside property with two large ballrooms, several boardrooms and a unique floating venue; suitable for conferences, exhibitions and corporate dinners (large capacities and flexible setups). (cinnamonhotels.com)

5. Taj Samudra Colombo — traditional luxury hotel with multiple halls and landscaped lawns; can host intimate meetings to very large gatherings (venues and lawns quoted to accommodate up to ~2,000); strong reputation for banquets and business events. (tajhotels.com)

6. The Kingsbury Colombo — central waterfront hotel with large Balmoral ballroom and flexible meeting spaces (largest ballroom capacity reported up to ~800); often used for conferences, product launches and corporate galas. (businesstravelnews.com)

7. The Galadari Hotel Colombo — long‑standing business hotel with many meeting rooms and sizeable banquet/exhibit capacity (multiple meeting rooms, largest room capacities several hundreds); good for exhibitions and conferences needing contiguous meeting space. (businesstravelnews.com)

8. Courtyard / Marriott (Colombo city‑centre projects) — international brand standards, meeting rooms and group packages (Courtyard by Marriott Colombo opened as a city‑centre option with meeting rooms suitable for business groups). (Check current openings/meeting‑packages for exact capacity and availability.) (ceo.lk)

Quick planning tips

• Ask each hotel for: detailed room capacities (theatre/classroom/banquet), included AV (microphones, projectors, technical support), Wi‑Fi bandwidth guarantees, catering packages, and group‑room block rates. (hilton.com)
• For very large exhibitions or >2,000 attendees compare hotel ballrooms vs. the Sri Lanka Exhibition & Convention Centre (SLECC) + nearby hotels for overflow/rooming. (en.wikipedia.org)

If you want, tell me:

• your expected attendee count, preferred area of Colombo (Galle Face / Fort / Beira Lake), dates (or a date range) and any must‑have features (simultaneous translation, exhibition space, breakouts), and I’ll shortlist 2–3 hotels with capacities, estimated room rates and direct sales contacts.