Purpose: Magseed localisation is increasingly popular in breast surgery due to its ability to be inserted any time pre-operatively without signal decay, lack of ionising radiation, ease of operator use, and low rates of migration. We reviewed the outcomes and complications using this novel technique for excision of non-palpable breast lesions and targeted axillary lymph nodes. Methods: Prospective data was collected from June 2022 to December 2024 in 500 patients who had Magseed localisation of breast and axillary lesions in a tertiary Australian metropolitan hospital. Results: A total of 555 Magseeds were used in women aged 22 to 87 years old. The majority had a single breast lesion localised with a single Magseed (n=473), with multiple Magseeds for multiple lesions within the same breast in 14 cases. Bracketing was used in 20 cases. Targeted axillary dissection was performed for 13 patients. There were 363 wide local excisions (n=326 level 1 oncoplasty, n=37 level 2 oncoplasty), and 144 excisional biopsies. Pre-operative biopsies included invasive cancer (n=297, 56.14%), DCIS (n=69, 13.04%), and B2/B3/B4 pathologies (n=163, 30.81%). Median time from Magseed insertion to surgery was 7 days, with 36 placed on the day of surgery, and the maximum duration was a Magseed inserted 173 days pre-operatively. Mean duration of surgery (skin incision to specimen out) was 18 minutes. Median specimen weight was 20.8g. Re-excision rate for positive or close margins was 19.8% (n=72), and the migration rate (>10mm) was 2.9% (n=16). There were no major complications relating to the Magseed recorded. Conclusion: Magseed localisation in breast surgery is a safe and reliable technique. Its ability to be inserted any time before surgery, ease of operator use and low migration rates has resulted in our unit transitioning to using it as the primary localisation technique, replacing ROLLIS which had constraints in COVID-related surgical delays and radiation issues.