What Is Offside in Hockey? Every Rule and Review Situation

A player is offside when he crosses the opponent's blue line before the puck does. No attacking player may enter the attacking zone ahead of the puck — the puck goes in first, or the play is dead. Skates decide it, not sticks and not bodies, and the whistle sends the game to a faceoff in the neutral zone.

That covers 95 percent of what you'll see. The other 5 percent — delayed offside, tag-ups, coach's challenges and goals wiped out by an inch of skate blade — is where the rule gets genuinely interesting, and it's all below.

Offside at a Glance

The Blue Lines and the Three Zones

An NHL rink is 200 feet long and 85 feet wide. Two blue lines cut it into three zones, each blue line sitting 64 feet out from the goal line behind it (75 feet from the end boards). The 50 feet between the two blue lines is the neutral zone.

Zones are named from each team's perspective. The end where a team defends its own net is its defensive zone; the end where it attacks is its attacking zone. Same ice, opposite names depending on which sweater you're rooting for.

Offside polices the moment a team moves from the neutral zone into the attacking zone. Without it, a forward could park next to the opposing goaltender and wait for a 150-foot pass. The rule forces the whole attack to enter together, behind the puck — which is why you see forwards visibly slam on the brakes at the blue line several times a period.

The blue line's twin, the center red line, governs the other big non-penalty stoppage. That one is covered in What Is Icing in Hockey? The Rule, Explained Simply, and the two rules are best learned together.

Skates Decide — and the Blue Line Has a Ceiling

The rule turns on one body part. A player's stick can be a foot inside the zone, his torso can be leaning over the line, his helmet can be halfway to the net — none of it matters. Only skates.

A player is onside when, at the instant the puck completely crosses the leading edge of the blue line, either of his skates is in contact with the line or on his own side of it. He only becomes offside when both skates are fully across.

Then comes the change most new viewers find surprising: the blue line has a ceiling. For the 2020-21 season the NHL redefined "his own side of the line" as a vertical plane rising upward from the leading edge of the blue line. A skate that is off the ice but still above the line keeps the player onside.

The wording the league adopted is precise:

A player is on-side when either of his skates are in contact with the blue line, or on his own side of the line, at the instant the puck completely crosses the leading edge of the blue line. On his own side of the line shall be defined by a "plane" of the blue line which shall extend from the leading edge of the blue line upwards.

Before that change, a skater who lifted his back foot a half-inch off the ice while straddling the line was offside, and goals were erased on exactly that technicality. Roughly 14 of the 56 offside challenges overturned in the previous season would have stood as goals under the new plane rule.

The NHL tightened the language again for 2025-26, defining a "skate" as the blade of the skate only and specifying that a puck carrier must have possession and control with his stick before both skates cross the line — closing a loophole for players who kicked the puck ahead of themselves.

Delayed Offside and the Tag-Up

Not every offside stops play immediately. If an attacking player crosses the line early but his team does not have control of the puck in the zone, the linesman raises his arm and signals delayed offside. The clock keeps running and nobody blows a whistle.

The attacking team can wipe the infraction away by clearing out: every attacking player returns to the neutral zone, at which point the delayed offside is over and they can pour back in legally. That retreat is called a tag-up.

Three things end a delayed offside immediately, with a whistle:

• An attacking player in the zone touches the puck.
• An attacking player shoots on goal.
• An attacking player checks an opponent.

You will see this every game: a forward gets caught deep, and for two or three seconds the entire attacking unit sprints backward to the blue line while the linesman holds his arm up. Then they turn and attack again. That's a tag-up.

Where the Faceoff Goes

An ordinary offside sends the game to the nearest faceoff dot in the neutral zone, five feet outside the blue line. It's a mild consequence — the attacking team loses its zone entry but restarts close to where it was.

Intentional offside is treated much more harshly. If a team deliberately goes offside to buy a stoppage, the faceoff moves all the way back to the offending team's own end zone. Same idea as icing: the league removes the benefit the team was trying to buy.

Neither is a penalty. Nobody goes to the box and no team plays short-handed. The situations that actually put a team down a man live in NHL Penalty Rules: Minor, Major, Misconduct and Match, Explained.

The Review Side: How Offside Became Reviewable

For most of NHL history, an offside missed by a linesman stayed missed. The play that changed that came on February 18, 2013 in Denver. Colorado's Matt Duchene drifted into Nashville's zone so far ahead of the puck that the broadcast crew was left sputtering, collected it and scored. Two officials were looking right at it. No whistle.

The Duchene goal is the play most often credited with pushing the league toward video review of offside. The coach's challenge was approved in the rules package for the 2015-16 season, covering offside and goaltender interference on goals, and costing a team its timeout if the challenge failed.

The system has been reworked three times since:

2017-18. The league added real teeth. Under the new Rule 78.7, a team that challenged for offside and lost was assessed a minor penalty for delay of game — and no longer needed to hold a timeout to challenge in the first place.

2019-20. The NHL expanded review substantially. Coaches could now also challenge a missed stoppage before a goal — a puck out of play, a hand pass, or a high stick on the puck — and challenges became unlimited. The penalty structure moved to its current form: a minor penalty for a team's first failed challenge in a game, and a double minor for every one after that. Referees also gained the power to review major penalties and reduce them.

Two 2019 playoff plays drove that overhaul: a missed hand pass moments before San Jose's Erik Karlsson scored an overtime winner against St. Louis in the Western Conference Final, and a five-minute major on Vegas' Cody Eakin that the league later conceded was wrong — San Jose scored four power-play goals on it and won the series.

2024-25. Coaches gained one more challenge: a delay-of-game penalty for shooting the puck over the glass, which is not a penalty if the puck deflects off the glass first — a deflection referees can easily miss in real time.

Every challenge is decided by the NHL's Situation Room in Toronto rather than the referee on the ice, and the standard for overturning is strict: the video has to be conclusive. Fans used to the NBA's and NFL's systems will notice the differences — see NBA Coach's Challenge Rules Explained and NFL Challenge and Replay Rules: How Many Challenges Does Each Team Get.

What Is and Isn't Reviewable

The key point: offside is only reviewable when it produces a goal. A blown offside that leads to nothing is gone forever. The challenge exists to protect the scoreboard, not the rulebook.

Goals That Got Wiped Out

Aleksander Barkov, Game 6 of the 2024 Stanley Cup Final. Florida trailed Edmonton 2-0 and appeared to cut the lead with 51 seconds left in the second period. Oilers coach Kris Knoblauch challenged, the Situation Room ruled Barkov offside, and the referee announced: "After video review, at 19:09, the player was offside. No goal." Edmonton scored again before the period ended and forced a Game 7, which Florida won to claim the Cup.

The 2026 Stanley Cup Final, Game 2. A Vegas goal that would have made it 3-2 was wiped out for goaltender interference on a Carolina challenge. The Hurricanes scored on the resulting power play and won 4-3 in overtime, then took the series 4-2 for the franchise's second Stanley Cup.

Matt Duchene, 2013. Still the reference point. The goal counted. The rule didn't exist yet.

The Two-Line Pass Rule the NHL Deleted in 2005

Until 2005, hockey had a second offside rule, and it shaped the sport for six decades.

The two-line pass rule, introduced in 1943, made it illegal to pass the puck from inside your own defensive zone to a teammate who was already past the center red line. A pass that crossed two lines — your blue line and the red line — was whistled dead as an offside pass.

The intent was anti-cherry-picking. The effect, by the 1990s, was the neutral zone trap: a defensive team stacked all five skaters between the blue lines, knowing any pass over their heads was automatically illegal. Scoring bottomed out at 2.57 goals per team per game in 2003-04.

The NHL eliminated the two-line pass coming out of the 2004-05 lockout, in the same package that added the goaltender trapezoid and the no-line-change-after-icing rule. Scoring jumped to 3.03 goals per team per game in 2005-06, and the stretch pass — a defenseman firing the puck 100 feet to a forward already flying through the neutral zone — became a weapon rather than a violation.

Only one offside line remains today: the blue line. That's why a modern rush can go from a defenseman's stick in his own corner to a scoring chance in about four seconds, and why teams change lines the way they do — see How Many Players Are on an NHL Roster? Lines, Pairings and Scratches.

FAQ

What is the offside rule in hockey? An attacking player may not cross the opponent's blue line before the puck does. If he does and his team then plays the puck in the zone, play is stopped and a faceoff is held in the neutral zone.

Does your whole body have to be onside? No. Only your skates count. A stick, an arm or a leaning torso across the line is irrelevant — you're onside as long as one skate is touching the blue line, behind it, or in the air above it.

When did the NHL change the offside rule about skates in the air? For the 2020-21 season. The league defined the blue line as extending upward as a vertical plane, so a skate lifted off the ice above the line keeps a player onside. The rule was tightened again in 2025-26 to specify the blade of the skate.

What is a delayed offside? The linesman raises his arm instead of blowing the whistle because an attacking player entered the zone early but his team hasn't touched the puck. The attackers can clear the zone — "tag up" — and it disappears.

Where is the faceoff after an offside? At the nearest neutral-zone faceoff dot, just outside the blue line. If the linesman rules the offside was intentional, the faceoff instead goes all the way back to the offending team's defensive zone.

What happens if a coach's challenge for offside fails? The goal stands and the challenging team takes a minor penalty for delay of game. Every additional unsuccessful challenge in the same game is a double minor — four minutes.

Can you challenge an offside that didn't lead to a goal? No. The offside challenge only exists to review a goal. A missed offside that produced nothing on the scoreboard cannot be reviewed.

Is offside a penalty? No. It's a stoppage in play — nobody serves time and no team plays a man down.

Why did the NHL get rid of the two-line pass rule? To break up the neutral zone trap and raise scoring. It worked: goals per team per game rose from 2.57 in 2003-04 to 3.03 in 2005-06, the first season without the rule.