Background: Growing awareness about breast implant-related adverse events has stimulated the demand for large, independent data resources. For this, data from breast implant registries could be combined. However, that has never been achieved yet. Methods: Real-world data from four currently active national breast implant registries were used. All permanent breast implants from the Australian, Dutch, Swedish, and American registries were included. A subpopulation present across all registries between 2015 and 2018 was subsequently selected, including only permanent breast implants inserted during primary surgery for breast reconstruction or augmentation in patients without previous breast device surgery. Nationwide coverage, patient and implant characteristics, infection control measures, and revision incidences were analyzed. Results: A total of 207,189 breast implants were registered. Nationwide coverage varied between 3% and 98%. The subpopulation included 111,590 implants (7% reconstruction, 93% augmentation). Across the registries, mean patient age varied between 41 and 49 years (P < 0.001) for reconstruction and 31 and 36 years (P < 0.001) for augmentation. Variation was observed in implant preferences across the countries and over the years. Infection control measures were most frequently registered in Australia. Cumulative revision incidence at 2 years ranged from 6% to 16% after reconstruction and from 1% to 4% after augmentation. Conclusions: For the first time, independent, national, registry-based data from four breast implant registries were combined. This is a powerful step forward in optimizing international breast implant monitoring, evidence-based decision-making, and patient safety.