Previous research has shown that the reading abilities of learners of English as an additional language (EALs) become stronger during pre-sessional English for academic purposes (EAP) programs. However, it is not known what happens to the reading abilities of this population once they transition to undergraduate study. We report a longitudinal study in which EAL reading skills, including eye movements during silent reading, were tracked over a period of 50 months (4 years and 2 months) across three timepoints. The study timeframe spanned two critical phases: a 6-month period covering the delivery of a pre-sessional EAP program (Phase 1), and the subsequent 44-month period between the end of EAP instruction and the final year of undergraduate study (Phase 2). Data was collected on a range of reading and reading-related skills, including eye-movement measures of silent reading fluency, passage comprehension, receptive vocabulary, and phonological processing. Results of piecewise linear mixed-effects regression models showed that although select measures, such as vocabulary and reading comprehension, continued to grow after EAP instruction, the rate of change for all measures was greater during EAP instruction compared to undergraduate study. Moreover, reading skill growth measured during EAP instruction predicted reading performance over 3 and a half years later. Results from hierarchical regression modelling show that Phase 1 change in reading skills contributed significantly to end-of-degree ability for virtually all reading measures, an effect that holds even when baseline ability is controlled for. This study provides the first comprehensive picture of reading development across EAP instruction and beyond.