I took the Portsmouth to Santander route last summer, and I'd say it's ideal if you prefer a shorter drive to the ferry port in the UK. The journey itself was smooth, and I was pleasantly surprised by the onboard facilities—good food options, a comfortable cabin, and even entertainment options if you're traveling with family. For those wondering about the options available, this site https://ferrytospain.co.uk/ breaks down the UK to Spain ferry routes really well, making it easy to compare journey times and costs. For example, if you're after a faster route, Portsmouth to Santander takes around 24 hours, while Plymouth to Bilbao might stretch to 32 hours but gives you a bit of a scenic cruise along the coast. Personally, I think the choice between routes often boils down to how much driving you're up for before boarding and whether the departure port’s schedule fits with your travel plans.