Switzerland
Practice Relating to Rule 3. Definition of Combatants
Switzerland’s Regulation on Legal Bases for Conduct during an Engagement (2005) states: “
Combatants are members of the armed forces of a party to the conflict,
with the exception of medical and religious personnel. In war, they may engage in harmful acts as long as they comply with the rules of the law of armed conflict.”
The Regulation further states that a wounded combatant who continues to shoot “remains a combatant until he lays down his weapons”.
The Regulation also states that “[t]he civilian police are not part of the belligerent forces, as long as they do not take part in the fighting and are not integrated into the armed forces”.
The Regulation further states: “Airborne troops – descending by parachute individually or in formation – are considered combatants”.
The Regulation also states: “Prisoners of war who rejoin their own forces after an escape are again considered combatants.”
Switzerland’s ABC of International Humanitarian Law (2009) states:
Combatants
In an international
Armed conflict all members of the armed forces of a party to the conflict are considered combatants, with the exception of medical and religious personnel. Combatants may take part in licit acts of war, for which they may not be subjected to criminal prosecution or brought to court (“combatants’ privileges”). In certain circumstances persons who participate in an uprising to defend their national territory are also accorded the status of combatants, as are militia fighters, volunteers and members of resistance movements. Combatants who are captured have a right to the status and guarantees accorded to
Prisoners of war.

[emphasis in original]
The glossary further states: “Only combatants are authorised to take a direct part in hostilities, that is to say, in combat.”
In 2010, in its Report on IHL and Current Armed Conflicts, Switzerland’s Federal Council stated:
Existing international humanitarian law treats non-State actors in a different manner depending on whether the situation is an international armed conflict or a non-international armed conflict.
In fact, in international armed conflicts, there are two categories of persons, combatants and civilians, the first having the right to take a direct part in hostilities. …
International humanitarian law establishes criteria for the granting of combatant status. It is primarily for members of the armed forces of a party to the conflict but also for members of other militias. For this, combatants must carry their arms openly, be recognisable (generally by a uniform), be under a responsible command and act in conformity with international humanitarian law in their operations.
Persons not falling in this category are civilians. They notably benefit from protection against direct attacks, provided that and as long as they do not take a direct part in hostilities. This participation does not however constitute a violation of international humanitarian law but entails the loss of the protection against attacks granted to civilians. …
In non-international armed conflicts, international humanitarian law does not provide for any particular status of combatant. Non-State actors participating in the conflict are civilians, who are protected against attacks provided that and as long as they do not take a direct part in hostilities. …
…
The analysis concerning private military and security companies does not fundamentally differ from that concerning other non-State actors. … As a general rule, they must be considered as civilians (independently of the uniform they wear), that is to say they do not have the benefit of any combatant privilege and are only authorized by national law to use arms in cases of legitimate defence.

[footnotes in original omitted]