NLL Rules: How Box Lacrosse Works

The National Lacrosse League (NLL) plays indoor box lacrosse, a faster and more physical version of the sport contested in an enclosed arena that looks much like an ice-hockey rink. Each team fields six players, five runners and a goalkeeper, rather than the ten used in outdoor field lacrosse, and the tighter space produces a high-scoring, contact-heavy game.

Box lacrosse’s confined boards, shot clock and heavy body contact give the NLL a distinct rhythm that fans often compare to hockey. If your only exposure to the sport is the outdoor field game, the indoor version can feel like a different sport entirely. Here are the core NLL rules and what makes box lacrosse tick.

The arena and the six-a-side setup

Box lacrosse is played inside an arena, frequently a converted hockey rink with the ice covered, surrounded by boards that keep the ball in play. Instead of the sprawling outdoor field, the action is packed into a compact rectangle, which is why the game is so fast and physical.

Each side has six players on the floor: five runners and a goalkeeper. That is four fewer than a field-lacrosse team, and the difference in numbers is one of the biggest contrasts between the codes, as covered in our comparison of box lacrosse vs field lacrosse and our rundown of how many players are on a lacrosse team.

The shot clock and continuous play

A defining NLL rule is the shot clock: once a team gains possession, it has a limited time to get a shot on goal or it surrenders the ball. This forces constant attacking and prevents teams from stalling, a major reason box lacrosse produces so many goals.

Because the boards keep the ball live, play flows continuously, rebounds off the walls stay in, and possession can change in an instant. There is no going out of bounds along the sides the way there is on an open field, which keeps the pace relentless.

Physical contact and penalties

Box lacrosse permits robust body checking within the rules, and the tight quarters mean collisions are frequent. Illegal actions, slashing, cross-checking, tripping, roughing and the like, are punished with time in a penalty box, exactly like hockey. That creates power plays, where the penalized team plays a man down and the opponent has a numerical advantage.

Fighting is against the rules and penalized, but, as in hockey, it does occur, and offenders serve time in the box rather than being automatically ejected the way many other sports would eject them.

NLL box lacrosse versus field lacrosse

The quickest way to grasp NLL rules is to see them next to the outdoor field game.

Feature	NLL (box)	Field lacrosse
Players per side	6 (5 + goalie)	10
Setting	Enclosed arena with boards	Open outdoor field
Ball out of play (sides)	Stays live off boards	Goes out of bounds
Shot clock	Yes	Yes (varies by level)
Style	Very physical, high-scoring	Physical, more spread out
Goalie gear	Larger, hockey-style padding	Lighter, smaller net

Goals, goalies and scoring

The NLL goal is smaller than a field-lacrosse net, and box goalkeepers wear bulky, hockey-style padding to fill it and block the close-range shots the tight arena produces. Attackers still cannot enter the goal crease, preserving the keeper’s protected zone.

Games are divided into quarters, and every goal counts as one point, with the higher total winning. The combination of a small net, a well-armored goalie and a ticking shot clock is what turns box lacrosse into a rapid-fire, shooting-heavy spectacle. Newcomers who want the broader fundamentals first can start with our lacrosse rules for beginners guide.

Substitutions and specialist roles

Like hockey, box lacrosse uses fast, on-the-fly substitutions through a designated bench area, so players cycle on and off constantly to keep fresh legs in a fast, physical game. Teams typically run offensive and defensive units that swap as possession changes, and specialists, such as sharpshooters and defensive stoppers, are deployed for specific situations.

The transition between offense and defense is a defining rhythm of the NLL. When possession flips, players sprint to change ends and the swapping units create a stop-start flow of full-strength attacks. This constant substitution, combined with the shot clock, is why the indoor game rarely has a dull, static stretch: someone is always attacking, and the clock is always ticking.

The bottom line

NLL rules boil down to box lacrosse: six a side in a boarded arena, a shot clock demanding quick offense, live play off the walls, legal body checking and hockey-style penalty boxes. It is the indoor, high-contact cousin of the field game, built for speed and scoring. Once you picture a hockey rink filled with lacrosse sticks, the NLL’s fast, physical style makes immediate sense.