In the present study, collagen type I obtained from fish skin by hydration (FSC) was used in measurements of electrical conductivity, while bovine Achilles tendon (BAT) was the control material. The measurements were carried out at the DC electric field E=1 kV/m. The DC voltage applied to samples was in the temperature range of 290–510 K and within the range of voltage current linearity, where the Ohm's law is obeyed. Current flowing through the sample was measured by an electrometer. All measurements were performed in air, under atmospheric pressure. The water content was determined using a Mettler–Toledo moisture analyzer. The analyzer automatically determined the mass after the temperature had settled. The measurements were performed every 10 K from 290 K to 473 K, as well as in the two-stage process at specific temperatures. The samples were heated for 15–20 minutes and, then, cooled down. The measurement at 380 K was to determine free water content. The measurement at 473 K, on the other hand, allowed to determine the amounts of bound and structural water. The maximum mass measurement error did not exceed 0.2%.