An infusion set, comprising: a base (132,300) having: a first side; an opposing, second side for contacting a patient's skin; a base guide with a port extending from the first side in a first direction; a base cannula extending from the second side in a second direction for insertion into the patient's skin; an engaging protrusion extending in the first direction from the first side of the base, the engaging protrusion having a cantilevered arm; and a locking structure comprising a slot recessed from the first side of the base; and a septum disposed within a fluid path between the port and the base cannula; and a fluid connector for connection with an external pump, wherein subsequent to engagement between the fluid connector and the base, the fluid connector is rotatable relative to the base in a first rotational direction to lock the fluid connector to the base, the fluid connector comprising: a connector cannula for insertion through the port and the septum when the fluid connector is connected with the base; an L-shaped leg configured to rotatably engage the cantilevered arm during locking of the fluid connector to the base, to prevent displacement of the fluid connector in the first direction relative to the base and, once the fluid connector is locked to the base, prevent rotation of the fluid connector in the first rotational direction relative to the base; a cantilevered tab configured to engage the locking structure (260,) wherein upon locking the fluid connector to the base, the interaction of the locking structure and the cantilevered tab prevents rotation of the fluid connector in a second rotational direction opposite to the first rotational direction but permit displacement of the fluid connector in the first direction relative to the base. a first side; an opposing, second side for contacting a patient's skin; a base guide with a port extending from the first side in a first direction; a base cannula extending from the second side in a second direction for insertion into the patient's skin; an engaging protrusion extending in the first direction from the first side of the base, the engaging protrusion having a cantilevered arm; and a locking structure comprising a slot recessed from the first side of the base; and a septum disposed within a fluid path between the port and the base cannula; and a fluid connector for connection with an external pump, wherein subsequent to engagement between the fluid connector and the base, the fluid connector is rotatable relative to the base in a first rotational direction to lock the fluid connector to the base, the fluid connector comprising: a connector cannula for insertion through the port and the septum when the fluid connector is connected with the base; an L-shaped leg configured to rotatably engage the cantilevered arm during locking of the fluid connector to the base, to prevent displacement of the fluid connector in the first direction relative to the base and, once the fluid connector is locked to the base, prevent rotation of the fluid connector in the first rotational direction relative to the base; a cantilevered tab configured to engage the locking structure (260,) wherein upon locking the fluid connector to the base, the interaction of the locking structure and the cantilevered tab prevents rotation of the fluid connector in a second rotational direction opposite to the first rotational direction but permit displacement of the fluid connector in the first direction relative to the base. a connector cannula for insertion through the port and the septum when the fluid connector is connected with the base; an L-shaped leg configured to rotatably engage the cantilevered arm during locking of the fluid connector to the base, to prevent displacement of the fluid connector in the first direction relative to the base and, once the fluid connector is locked to the base, prevent rotation of the fluid connector in the first rotational direction relative to the base; a cantilevered tab configured to engage the locking structure (260,) wherein upon locking the fluid connector to the base, the interaction of the locking structure and the cantilevered tab prevents rotation of the fluid connector in a second rotational direction opposite to the first rotational direction but permit displacement of the fluid connector in the first direction relative to the base.