The permeation through and desorption of hydrogen from cathodically charged microalloyed API 5L X65 and low alloy ASTM A182 F22 steels were investigated with the aim to analyse the trapping parameters by means of the electrochemical method developed by Devanathan and Stachurski. The lattice diffusivity of hydrogen as well as the amounts and distribution of the diffusible and trapped hydrogen were found by means of partial permeation transient. Crown Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.