Time-depth recorders paired with geolocation sensors or GPS loggers in Aotearoa, New Zealand were used to quantify the diving ecology of three Procellaria petrel species. All three species dove faster than the current best-practice longline sink rate of 0.5 meters/second, highlighting that the risk of interaction with these species is still present. There were also significant differences in diving behavior among and within species, including diurnal trends, sex-specific differences, and for black (P. parkinsoni) and Westland petrels (P. westlandica), changes in diving behavior across the breeding period. These results highlight the necessity of ensuring that bycatch mitigation methods take the strong diving capabilities of these three species into account. This includes night setting when many seabirds are less active and when dives are shallower, use of tori lines for smaller vessels, and a 20m threshold for hook-shielding or bait-setting devices (or combining these devices with bird-scaring devices and/or additional weighted branch lines to protect hooks to 20m). Furthermore, it can be beneficial for custom/target-specific bycatch mitigation methods being developed to take into account the necessary ecological context.