Non-tuberculous mycobacteria (NTM) are waterborne opportunistic pathogens that can cause serious infections in individuals with lung conditions and/or compromised immunity. This study investigated NTM aerosolisation from showers, assessed potential mitigations, and evaluated NTM aerostability – factors influencing inhalation exposure risk. Two naturally NTM-colonised showers with identical showerheads were studied in an unventilated room and a highly ventilated room (14-15 air changes/hour) in a model hospital ward. Air samples were collected 170-185cm from showerheads, with and without a shower curtain, during 5-minute shower runs, using six-stage Andersen and slit-to-agar samplers. NTM were cultured then identified by MALDI‑ToF. Aerostability was assessed by nebulising NTM suspensions, capturing aerosols on spider‑silk microthreads, and quantifying viability by culture over 96 hours at 20°C and 40% or 60%RH. NTM from shower aerosols were significantly higher in the unventilated room (~1.3x10⁴ cfu/m³) than the highly ventilated room (~5.6x10³ cfu/m³), with no significant effect of shower curtain use. Most NTM-containing aerosols (72.9-80.1%) were ≤2.1µm, capable of reaching terminal bronchi and/or alveoli. Ventilation reduced NTM-containing aerosols ≤2.1µm and cleared NTM 15-30 minutes post-shower, whereas without ventilation NTM persisted 220 minutes. NTM exhibited high aerostability. M. chimaera showed no significant decline over 96 hours. M. chelonae declined by 24-48 hours but remained viable at 96 hours, with significantly greater recovery at 60% than 40%RH. Showers generated high concentrations of respirable NTM-containing aerosols capable of deep lung deposition. Aerosolised NTM persist and remain viable, highlighting ventilation as a key mitigation for NTM exposure risk.