The single most important factor in a beach resort — more than the room category, the food program, or the amenities — is the beach itself. Hotel marketing rarely distinguishes between a wide, clean, calm beach with gentle waves and a narrow, rocky shore with strong currents. The photography won't tell you. You need to look at satellite imagery and recent guest reviews specifically about the beach conditions.
Water clarity and current matter enormously for swimming and snorkeling. The Caribbean windward coast has rougher conditions than the leeward coast. The Maldives inner atolls have calmer water than outer atolls. Thai islands vary dramatically between east and west coast conditions by season. Choosing a beach resort without checking ocean conditions is a genuine planning failure.
Room categories in beach resorts create significant price gaps. Ocean view vs ocean front vs overwater vs beach villa — the price difference between the lowest and highest room categories at the same resort can be 5x. The overwater villa category in particular commands enormous premiums (often $1,000+/night) for the aesthetic experience of being above water.
Monsoon season affects beach resorts dramatically. Booking a Thailand beach resort during monsoon season (May–October on the west coast) means intermittent heavy rain, choppy seas, and reduced visibility for water activities. This can still be a reasonable choice at 30–50% reduced rates if you're prepared for variable weather.
For the best combination of quality beach and hotel: the Maldives (remote but unmatched), Turks and Caicos (consistent calm water and sand quality), Bali's Seminyak (surf beach culture, reliable infrastructure), and Phuket's Kata Noi (sheltered bay, clean water, excellent hotel supply).