It would be convenient if one platform were reliably the cheapest and the other two could be safely ignored. In practice, none of the three major platforms holds a consistent, universal price advantage — each one wins often enough, in different enough circumstances, that skipping any of them means occasionally missing the actual best deal.
Booking.com's broad global reach and large negotiated inventory tends to make it competitive almost everywhere, and it's often strong in Europe and at larger international chain properties where its distribution relationships run deep. It's a reasonable default, but "reasonable default" and "always cheapest" are different claims.
Agoda's regional strength across Southeast Asia in particular comes from deep, long-standing relationships with independent hotels and resorts in that region, and it not uncommonly undercuts the other two platforms meaningfully on properties in Thailand, Indonesia, the Philippines, and nearby markets.
Trip.com carries similar regional strength focused on mainland China, Hong Kong, and parts of East Asia, along with periodic promotional pricing tied to its own marketing calendar that can create short-lived but real discounts unrelated to the hotel's underlying rate at all.
None of these patterns are guarantees for any specific booking — they're just tendencies. The only dependable method is checking the actual room, at the actual hotel, for the actual dates, across all three, since the general pattern and the specific outcome frequently diverge.
