Simple Summary Long-term surveillance following radiotherapy for choroidal melanoma is important for detecting recurrence. There is a perceived notion that regular ultrasonography is required to detect recurrence. The skills required to perform ocular ultrasound are not widely available, which can prevent patients being seen close to home. We aimed to determine whether local treatment failure can reliably be detected with colour fundus photography alone. We found that in 74 out of 75 patients (98.7%), with a clear view of their fundus, recurrence could be detected using colour photography alone. One patient with a clear fundal view developed extraocular extension which was detected on ultrasound without visible change in the intraocular part of the tumour. We conclude that most treated choroidal melanomas can be monitored without ultrasonography if they can be adequately imaged with colour photography. Abstract Prompt detection and treatment of local treatment failure after radiotherapy for choroidal melanoma optimises any opportunities for conserving vision and the eye, possibly reducing an increased risk of metastatic disease. Long-term surveillance is therefore required but is hampered by the perceived need to perform ultrasonography, which may not be available at a patient’s local hospital. The aim of this study was to determine whether local treatment failure can reliably be detected with colour fundus photography alone, and, if so, in which patients. Patients were included in the study if diagnosed with local treatment failure between April 2016 and February 2021 after eye-conserving therapy for choroidal melanoma. Wide-field colour and fundal autofluorescence (FAF) images, optical coherence tomography (OCT), and ultrasonography (US) were analysed by two of the authors (GN and UH). The cohort included 87 patients with local treatment failure. In 75 patients with clear media, tumour progression was detected by colour photography alone in 74 (98.7%) patients. Sensitivity was not increased by the addition of either OCT or AF. One patient with clear media developed extraocular extension detected with US without visible change in the intraocular part of the tumour. In the other 12 patients, US was required because of opaque media and a consequently poor fundal view. Local treatment failure after radiotherapy for choroidal melanoma is detected in 98.7% of cases with colour photography when the media are clear. Ultrasonography is useful when photography is prevented by opaque media or tumours having locations in the far periphery.