Brexit has caught up with the Vodafone UK SIM card, which I detailed 2.5 years ago in this post. While it is still a good option for UK travelers, the value proposition will become more complicated (that is to say, more expensive) beginning June 8, 2022 for travelers outside the UK.
Whereas previously a Vodafone Big Value Bundle included roaming in much of Europe, to roam in their Zone B (49 countries in Europe) you must now also purchase their "European Roaming passes, available as £8 for 8 days or £15 for 15 days."
CORRECTION: the £8 for 8 days or £15 for 15 days pricing may be for monthly subscribers. The Vodafone Extras page shows Pay as You Go pricing as £15 for 8 days or £25 for 15 days, covering 73 countries in their Zone D. I haven't found a cheaper PAYG option for their 49 Zone B European destinations.
For those who already own the Vodafone UK SIM, here is what I've worked out:
For a 1 or 2 week trip, you could buy their smallest Big Value Bundle (currently £10, with 7GB data, unlimited phone minutes and text) plus the new 8 day or 15 day European Roaming pass.
At £18 (Big Value Bundle + 8 day pass) or £25 (Big Value Bundle + 15 day pass) this is still significantly cheaper than my Verizon International plan options for the same length trip, assuming daily usage at $10 / day.
For a 3 week trip, you'd need to buy a Bundle, plus an 8-day and a 15-day pass, total £33.
For a 4 week trip, you'd need to buy a Bundle, plus two 15-day passes, total £40.
Since I already own the Vodafone UK SIM and have it set up, it's still probably good value for my trip to Portugal in July (I just missed that June 8th timeframe) though I may consider alternatives for later trips. For travelers outside the UK who are considering a Europe SIM for the first time, other options are likely to be less complicated and cheaper.