In all basic artistic swimming positions, the arm positions are optional for the swimming. Additionally, toes must be pointed and the legs, body and neck all must be fully extended unless otherwise noted.
Back layout: The swimmer's body is extended with the face, chest, thighs and feet at the surface, where the head - most notably, the ears - hips and ankles are aligned.
Front layout: The swimmer's body is extended with the head, upper back, buttocks and heels at the surface, where the head and face may be in or out of the water.
Ballet leg: The swimmer's body is in a back layout position with one leg extended perpendicular to the surface. May be performed at the surface or in a submerged position, where the water line would be between the knee and the ankle. May also be performed as a "double ballet leg position," where both legs are perpendicular to the water's surface, at either a surface or submerged position.
Flamingo: One of the swimmer's legs is extended perpendicular to the surface, with the other leg drawn inward to the chest. The mid-calf of the non-vertical leg, foot and knee are parallel to the water's surface. This position can be performed at the surface or in a submerged position, where the water level would fall between the knee and the ankle of the extended leg.
Vertical: The swimmer's body is fully extended and perpendicular to the surface, with legs together and head facing downward. The head - most notably, the ears - hips and ankles are aligned.
Crane: The swimmer's body is in a vertical position, with one leg extended forward from the body at a 90-degree angle.
Fishtail: The swimmer's body is extended in a vertical position, with one leg extended forward from the body. This differs from the crane position because no matter if this move is performed at the surface, submerged or airborne, the foot of the extended leg remains at the surface. A "side fishtail position" is a variant of the fishtail position, where the swimmer's body is extended in the vertical position and one leg is extended sideways with the foot at the surface regardless of the height of the swimmer's hips in the water.
Tuck: The swimmer's body is as compact as possible, with a rounded back, legs together, heels close to the buttocks and head close to the knees. It can be performed at the surface or in a perpendicular position to the water's surface.
Front pike: The swimmer's body is bent at the hips to form a 90-degree angle, with legs extended together and the trunk extended with back and head in alignment.
Back pike: The swimmer's body is bent at the hips to form an acute 45-degree angle, with legs extended together and the truck extended with the back and head in alignment.
Dolphin arch: The swimmer's body is arched so that the head hips and feet conform to the arc being followed with legs together.
Surface arch: The swimmer's lower body is arched with hips, shoulders and head in a line while legs are together at the water's surface.
Bent knee: There are several bent knee positions, including front layout, back layout, vertical or arched positions. The swimmer keeps one leg bent, with the toe of the bent leg in contact with the inside of the straight extended leg at either the knee or thigh.
Tub: The swimmer's legs are bent together, while feet, knees and calves are parallel to the surface and thighs are perpendicular. The swimmer's head is in line with the trunk and their head is at the surface.
Split: The swimmer's legs are evenly split forward and backward and are parallel to the surface. With the lower back arched, the swimmer's hips, shoulders and head are on a vertical line. This can be done at the surface, with legs barely coming out of the water, or in an airborne position with legs above the surface.
Knight: The swimmer's lower back is arched as the hips, shoulders and head are on a vertical line. With one leg vertical, the other leg is extended backward, with the foot at the surface and as close to horizontal as possible. This position can be altered - called the "knight variant position" - if done completely submerged with the thigh and shin of the extended leg parallel to the surface of the water.
Adapted from the Official Rules of the sport from the governing body of artistic swimming, FINA.