Spacers are provided for maintaining annular tube spacing, particularly at tube ends, in coaxial tubing systems, while also proving fluid passages ways permitting fluid flow between tubes of the coaxial tubing system. The spacers may be made of conductive material for enabling electrical coupling of the inner and outer tubes, and thus grounding of the inner tube. The spacers define a retention groove extending around their periphery for receiving a crimped portion of the outer tube, so as to mechanically fix the spacer in a longitudinal position relative to the coaxial tubing system. Accordingly, the spacer does not rely on “springbuck” characteristics of bent coaxial tubing systems for fixation, and thus is suitable for use in both bend and unbent portions of coaxial tubing systems.