The NEL Space Fleet was the first institution created by The New Earth League at its founding in 2376. The fleet personnel are recruited from all member worlds and most ships do not have a majority of crew from a single world. The fleet is financed by the NEL treasury from world contributions. Its mission include: protecting all member worlds from outside attack, hunting down pirates and scavengers in League space, aiding member worlds in times of natural disaster and making strikes against outworld threats.

The fleet does not maintain ships or bases outside of the boundaries of member-world star systems, although occasionally it scouts nearby systems for potential trouble. Originally, the fleet also conducted exploration and contact with lost human colonies, but these functions were too often neglected by the admirals, and so The Space Patrol was created to take on those duties.

Fleet bases are never on the surface of a member world and so are subject only to NEL jurisdiction. The fleet is organized into Squadrons of 3-12 ships, commanded by a Commodore: Armadas of 3-12 Squadrons commanded by an Admiral, and Grand Fleets of 3-12 Armadas, commanded by a Grand Admiral.

The Fleet does have troops as well, used for security on bases and ships and for boarding actions. They are called the Corps of Armsmen and are fully integrated into the Fleet Rank structure. While the Armsmen do on occasion conduct surface raids, they don't exist beyond battalion (c.500 men) sized units and are never used in large scale or long term surface warfare. Those roles are reserved for member-world armies.