Previous front-tracking (front-following) algorithms for marine robots have been developed for - and applied to - coastal fronts such as wind-driven coastal upwelling fronts or river plume fronts. During the R/V Falkor cruise FK180528 in May-June 2018 we developed a new, universal front-following algorithm based on a novel concept of tracking front's axis. We successfully tested this algorithm by driving surface vehicles (Wave Glider and R/V Falkor) and an Autonomous Underwater Vehicle (AUV) along the large-scale open-ocean Subtropical Front in the Northeast Pacific.