The aims of this study were to 1) investigate the reliability of the Garmin Vector 3 (V3) pedals, and 2) compare power output and cadence between the Lode Excalibur Sport ergometer and the V3 pedals. Seven male cyclists completed 6 × 2-min sub-maximal cycling stages (100, 150, 200, 250, 300 and 350 W) and 2 × 10-s maximal sprints, completed on two occasions within seven days. A Mann-Whitney U test identified significant differences between the Lode Excalibur Sport and the V3 pedals at 150–350 W and during all-out sprinting ( P < 0.05) with a mean relative difference during sub-maximal cycling of 1.8%. Results also suggested there was no significant differences between the Lode Excalibur Sport and V3 pedals for cadence at all power outputs tested ( P > 0.05), with a mean relative difference of 0.2%. Results suggest that the V3 pedals are reliable for both power output and cadence with a coefficient of variation of <5.05% and <3.87%, respectively. Furthermore, the technical error of measurement for power output was 2.4 W–5.3 W between 100 W and 350 W, and <8.04 rev.min−1 for cadence at all power outputs tested. It is suggested that the V3 pedals are reliable and accurate during sub-maximal testing; however, the V3 pedals over-estimate power output during all-out sprinting.