Abstract We demonstrate the combined utility of distributed acoustic sensing (DAS) and repeat conductivity‐temperature‐depth (CTD) profiling for observing internal tide dynamics over a sloping seafloor. While DAS has been widely proposed as a method to infer ocean temperature variability from seafloor cables, quantitative in situ validation has been limited. Here we present the first published detailed comparison between DAS‐inferred bottom temperature fluctuations and near‐bottom temperature measured from high‐resolution yoyo‐CTD time series reaching 5 m above the seafloor, conducted over the EllaLink/GeoLab cable on the slope of Madeira. Linear regressions yield an empirical DAS temperature sensitivity of 21–37 µstrain K−1 ${mathrm{K} }^{-1}$, a factor 2.5–4 greater than commonly used theoretical estimates. The calibrated DAS record reveals semidiurnal internal tide bores propagating upslope to ∼ ${sim} $1,300 m depth, where propagation halts and transitions to a complex interference pattern. These observations highlight the potential of combining seafloor fiber sensing with targeted in situ profiling to observe near‐bottom internal tide breaking processes.