Great — here are hotels in Singapore known for having the best social atmosphere, grouped by the kind of vibe they offer so you can pick what suits you best.

Party / Pool & Resort Vibe

• Marina Bay Sands — Iconic integrated resort with rooftop SkyPark, multiple high‑energy bars, big restaurants and a nightclub (lots of people, events and late‑night options). (en.wikipedia.org)
• W Singapore — Sentosa Cove: bold, fashion‑forward design, large pool and the WOOBAR lounge (DJ nights, resort crowd and social weekend energy). (woobar.sg)

Rooftop & View‑driven Socials

• Andaz Singapore (Mr Stork) — Rooftop bar with 360° views and private teepee‑style booths; very social at sunset and evenings. (liveluxetravelco.com)
• The Fullerton Bay Hotel (Lantern) — Rooftop pool bar with panoramic Marina Bay views — relaxed but buzzy around showtimes and weekends. (bestrooftop.com)

Cocktail‑forward / Local Nightlife Magnets (great for meeting people)

• Amara Singapore (Jigger & Pony) — Home to Jigger & Pony, one of Singapore’s top cocktail bars — lively, convivial and popular with locals and visitors alike. (jiggerandponygroup.com)
• The Warehouse Hotel — Boutique hotel with a day‑to‑night lobby bar and cocktail program; intimate but social. (thewarehousehotel.com)

Trendy, Design‑Led Lifestyle Hotels

• M Social (Robertson/Clarke Quay area) — Philippe Starck–designed, with a buzzy restaurant/bar and easy riverside access to bars — popular with younger travellers and staycationers. (oyster.com)
• The Standard, Singapore — Newer lifestyle hotel with Café Standard, Kaya (izakaya + bar) and a lively pool/garden — built to attract both hotel guests and locals. (standardhotels.com)

Neighborhood / Riverside Nightlife Bases

• Park Hotel Clarke Quay — Large pool with pool bar and immediate access to Clarke Quay’s nightlife; practical pick if you want to step straight into the riverside scene. (oyster.com)
• SO/ Sofitel (1927 rooftop) — Rooftop bar 1927 with pool and city‑view lounge energy — a stylish CBD option with a social rooftop crowd. (asia-bars.com)

Quick planning tips

• Clarke Quay / Robertson Quay = easiest for bar‑hopping and casual nightlife; Marina Bay = big‑scale dining, rooftop and club scenes. (thebrokebackpacker.com)
• Weekends and sunset times are the busiest — book tables or rooms with pool/club access in advance. (Most hotel bars publish hours/reservation details on their sites.) (woobar.sg)

If you want, I can narrow this list to a specific neighborhood, budget (hostel → 5‑star), or travel dates and give a short shortlist with pros/cons and approximate price ranges.