1.) Competitors must follow the marked course in correct sequence from start to finish and must pass all control points.

2.) If a competitor skis on a wrong section or leaves the marked course, (s)he should return to the point where the error was made. In order to do so, the competitor may have to ski against the correct ski direction and shall be totally responsible for ensuring that there is no obstruction and for ensuring the other competitors are not endangered.

3.) Competitors must cover the whole distance on their skis using only their own means of propulsion. Help from outside pacemakers is not allowed.

4.) In classical technique competitions, the competitors must use classical technique only.

5.) In Interval Start competitions, any violation of classical technique (for example skating strides to maintain or increase the speed) will be considered to affect the results (due to improved time), and the jury will apply the appropriate sanction regardless of the time difference between skiers, even for a winning athlete.

6.) Obstruction is not allowed in any competition. Obstruction is defined as deliberately impeding, blocking, charging or pushing any competitor with any part of the body or ski equipment.

7.) Waxing, scraping or cleaning of the skis during competition is forbidden in freestyle technique competitions, but allowed in classical technique competitions, where the athletes may scrape their skis to remove snow and ice and add wax, if necessary. Competitors may only be handed tools or materials, but the athletes, themselves, must do everything else outside of the track without further assistance.

8.) Competitors must wear/use all the means of identification (bibs, leg numbers, timing chips) provided.

There are two styles of cross-country skiing: classic and freestyle. In classic races, skiers use the traditional striding technique. It can be compared to running on skis. The freestyle technique, which also is often referred to as skating, is more of a push out and glide motion where the skier makes lateral movements relative to the direction they are traveling.

Reasons for disqualification:

• Changing from one course to another
• Interfering with the opponent, accidentally or not
• Not passing through a gate correctly
• Stepping back

Violations typically occur in the following situations: 

• On the corners: If tracks exist on a corner, racers must stay within those tracks by using the classical technique. If no track exists on a corner, racers are allowed to use a turning technique by pushing off the inside of one ski to complete the turn. Sections of the course where a turning technique is allowed are marked for the racers.
• Switching tracks: Changing tracks in the middle of the race is legal. A cross-country racer will step from one set of tracks to another in an attempt to improve their position. If a racer changes tracks repeatedly, especially on hills where the steps can give them more power to ski the incline, they will be assessed a violation.
• Herringbone technique: Stomping up hills with skis in a V-pattern, known as herringbone technique, is legal until the skis begin to slide out from under the racer. Once a ski begins to slip, a racer has a tendency to push off from the inside edges. This is considered skating or freestyle technique, and the racer will be assessed a violation. 

If a racer is assessed two violations in a single race, referred to as yellow cards, that skier will be disqualified from the event. 

A skier false starts if they begin the race more than three seconds before the start signal.

During interval start or pursuit start races, skiers who commit a false start will not be recalled back to the start line. False start violations must be reported to the jury. For all competitions utilizing a mass start or heat start, any false start results in the entire race being restarted. The starter or the start gate must give a false start signal. Skiers are ushered to turn around and go back to the beginning of the race.

Here are the penalties according to the FIS International Ski Competition Rules:

• In interval start competitions or sprint qualifications, early start infractions should be sanctioned by a minimum time penalty of 15 seconds (the competitor’s actual skiing time + 15 seconds minimum penalty).
• In pursuit start competitions, early start infractions should be sanctioned by a time penalty equal to the time gained (posted start time minus actual start time) + 30 seconds minimum penalty
• In stage events, team sprint competitions or relay competitions, the jury can decide to substitute a DSQ with a three-minute time penalty
• Relay exchange infractions in relay competitions are subject to a minimum 30 second penalty plus the actual time gained by the false start
• Team sprint infractions are subject to a minimum 15 second penalty plus the actual time gained by the false start.

In cross-country skiing, the race finishes for each skier when the toe of their front boot crosses the finish line. A finish is not determined by the tip of a ski.

Electronic timing technology is used to identify official race finish times, like a photo finish system.

Protests can be made in the following circumstances:

• Against admittance of competitors or their competition equipment
• Against the course or its condition
• Against a competitor or against an official during the race
• Against disqualifications
• Against timekeeping
• Against instructions of the jury

A jury only must accept a protest if it is based upon physical evidence. A jury only is permitted to re-evaluate its previous decision where new evidence exists that relates to the original decision.

Appeals can be made in the following circumstances:

• Against the decision of the jury to terminate a race
• Against the recommendation of the jury that a terminated race should count for FIS points - against the official result. This appeal has to be directed exclusively against an obvious and proved calculation mistake.
• Appeals must be submitted to the FIS office only by the National Ski Association
• Appeals against jury decisions must be submitted to the Appeals Commission within 48 hours of their announcement
• The official results may be appealed to the Council via the FIS Office within 30 days for matters that are outside the competence of the jury
• Decisions concerning appeals are taken by the Appeals Commission - the FIS Court
• All appeals must be in writing. Proof and evidence are to be included

• Relay competitions in cross-country skiing are a distance of 4x7.5km for both men and women and begin as a mass start
• Relays consist of four legs: the first two are classical and the final two are free technique legs
• The total time of a relay team is the time between the start and team's final competitor crossing the finish line. The order in which the skiers finish the last relay leg determines which team wins.
• During the relay, the next skier begins when the current racer exchanges with the next team member in line. The exchange occurs when the current skier taps the next skier on their team with their hand while both are in the relay exchange zone.
• Relay exchange infractions will result in a minimum 30 second penalty