ONE Championship is the largest international promotion to feature traditional Muay Thai under glove rules, and its ruleset attempts to bridge Thai stadium tradition with international audience expectations. The rules differ in subtle but consequential ways from Lumpinee tradition.
ONE Championship Muay Thai bouts are three rounds of three minutes for non-title fights and five rounds of three minutes for championship bouts. The shorter format compared to Lumpinee's standard five rounds changes pacing dramatically — fighters cannot afford the slow opening rounds traditional in Thailand and must score from the opening bell.
ONE has historically experimented with open scoring announced after each round, which is unusual in combat sports and not standard practice in Lumpinee. The intent is to inform fighters and audiences who is winning and force action when behind, but critics argue it removes strategic ambiguity. The current implementation varies by event. The base scoring criteria align closely with Thai traditional scoring (kicks, knees, ring control, damage) but are applied per round rather than weighted toward the late rounds.
ONE Muay Thai bouts use 4-ounce or 6-ounce gloves depending on weight class and event format, which is significantly smaller than the 8-10 ounce gloves typical at Lumpinee. Smaller gloves transmit more power and produce more knockouts, which is part of the international audience appeal. Mouthguards and groin protectors are mandatory; headgear is not used in pro bouts.
Elbow rules at ONE depend on the specific event and weight class. Some bouts allow full elbows including to the head; others restrict elbows to the body or prohibit them entirely. The variation means fighters often need to prepare differently for each ONE booking.
Unlike Lumpinee where the clinch can run extensively, ONE Championship referees often break clinches more quickly to maintain action pace. A fighter who relies on extended clinch dominance — the muay khao style — can find themselves at a disadvantage when the referee restarts before they can do significant damage.