Hydrogen as energy carrier in the future low emission society is undisputed to obtain dramatically reductions in CO2 emissions. The demand for hydrogen is expected to increase significantly and production of hydrogen gas is possible from renewable sources (wind, solar, hydropower, biomass) or from fossil fuels. The “green” alternatives represented by fully renewable sources such as wind and solar cannot to date replace the fossil energy resources and hence the hydrogen produced from natural gas combined with carbon capture, utilization and storage (CCUS), can provide large scale quantities of emission free hydrogen to consumers, the so called “blue” hydrogen. Pipelines installed subsea or onshore are undisputed cost effective for transport of large volumes of natural gas over longer distances and will play and equivalent important role in the energy transition to low carbon solutions. Existing natural gas pipelines may be considered re-purposed for hydrogen service when these are available. From the North Sea the existing large diameter subsea gas export pipelines may have a future in transportation of hydrogen gas to the European continent. Each of these subsea pipelines in the range from 36” up to 42” may contribute significantly to the future potential hydrogen demand. This presentation is focused on interpreting gained knowledge in safe operation of hydrogen pipelines onshore for the future re-purposing or new installation of subsea pipelines for hydrogen service, in which material properties, load conditions and the modified criteria and strength utilization are essential factors for safe operation.