Within PrefHer (NCT01401166), patients and healthcare professionals (HCPs) preferred subcutaneous (SC) over intravenous (IV) trastuzumab. We undertook a prospective, observational time and motion study to quantify patients’ time in infusion chairs and active HCP time in PrefHer. Patients with HER2‐positive early breast cancer received four adjuvant cycles of SC trastuzumab (600 mg fixed dose via SC single‐use injection device [SID, Cohort 1] or SC handheld syringe [HHS, Cohort 2]) then four cycles of standard IV trastuzumab or the reverse sequence. Generic case report forms for IV and SC management, both in the treatment room and the drug preparation area, were tailored to reflect center practices. Patient chair time and active HCP time were recorded. We compared pooled Cohort 1 + 2 IV with Cohort 1 SC SID and Cohort 2 SC HHS mean times across eight countries and individually within them utilizing a random intercept generalized linear mixed‐effects model. Per session, the SC SID saved a mean of 57 min of patient chair time versus IV (range across countries: 47–86; P