Which Park to pick in Western Europe in May?

You're a bit all over the place there. You've identified parks in Spain, England, and The Netherlands, so I'm not sure how far out of you're way you want to go to visit a theme park. I would probably recommend whatever parks are proximal to your trip itinerary, but I would not build my entire vacation itinerary around a single theme park visit.

Europa Park in southwest Germany is widely considered to be one of the best parks in the world (though there are a few funny Disney knock-offs in the design). The park is large and there is a great mix of attractions.

Spain has Parque Warner in Madrid and Port Aventura in Barcelona, both look to be pretty good.

England has Alton Towers which is unique but the rest of the parks in the country are lackluster.

Yeah, to second Russell - tell us where abouts you're headed and we'll volunteer some tips.

Hey guys I am actually going to be in all those destination areas. I'd love to go to Europa park but I won't be in Germany however. Parque Warner might be an option. I can flip my day in Granada to Madrid. I am at least a short train ride or car rental away from a handful of others though. I am flexible what I do in those places except for Morocco and Romania. I am assuming there are no parks in those areas anyhow. Thanks for the advice. I appreciate it. Wherever I go I promise to give a good trip report.

My itin:
May 24-25 London
May 26 Bath, UK
May 27-28 Paris (Astr Parque or Disneyland?)
May 29-30 renting a car and exploring Belgium and Holland (Efteling?)
May 31- June 3 Lisbon
Jun 4-7 Marakesh
June 8-11 Seville and Granada (Parque Warner?)
June 12-14 Brasov

Looking at your itinerary, your best bet is probably Efteling. 2 days is just not enough to cover London (don't know if you've been there before), and I think you will be kicking yourself if you commit an entire day to venture out to Thorpe Park or Alton Towers when there's so much to see and do in London proper.

Similarly, 2 days to cover Belgium and the Netherlands will also be tight, but having a car makes taking a detour to Efteling a little more feasible.

If you're in Seville/Grenada (southern Spain), you're pretty far from any noteworthy theme park. Parque Warner is in Madrid, and the other good parks in Spain (Terra Mitica and Port Aventura) are both on the eastern Mediterranean Coast near Valencia and Barcelona. If you're flipping your itinerary to spend time in Madrid, you should explore Madrid, not an average, at best, theme park that used to be managed by Six Flags. Unless you have a car and feel like driving far, I would probably not try to squeeze a theme park day while you're in Spain.

Thanks so much Russell. I am probably going to do Efteling, as you suggested. Maybe my next trip I can do Europa Park, I've been to The UK, and France several times but not to Southern Spain so I will probably take in the historic sites.

Since you are in London.... Chances are you're going to visit what is arguably the worlds oldest theme park anyway.

I am talking about the Tower of London.

Wait, I hear you say, there are no rides at the tower of London, unless you count the travelator that takes you past the crown jewels.... Well, the key word in theme park is theme, not ride.

The Tower is arguably the oldest visitor attraction still operating. The Crown Jewels have been on display in some form since 1669, its had a ticket office since 1851 and over half a million people a year were visiting by the end of the 19th century. Buildings have been built within the tower grounds not to contemporary style, but to match the theme of existing buildings.... The nearby Tower Bridge is also built that way to match the tower.

It also perhaps had one of the first examples of discounted tickets being available... at some points in the 18th century if you brought a dog or cat for the animals in the managerie to eat, you got in free. I don't think that would work at DAK...

Personally, I'd recommend taking more time in fewer places. Especially once you take travelling into consideration, you're not going to have time to do much more than see a few touristy spots in each place. If you've been to London and Paris before, why not use those days to see a little more of the countries new to you? We've got such a rich history in the various cultures here, the joy really exists in getting under their skin rather than jumping from one hotspot to the next.

Also - maybe consider swapping some of your Lisbon days with Porto - or at the very least make it a day trip. It's the smaller of the two cities for sure, but is so much more unique and charming. It feels much more characteristically Portuguese. (Plus if you want to tack on a theme parky thing, they've got an odd attraction called "World of Discoveries" that only takes a couple hours.)

Definitely don't do Madrid just for the sake of Parque Warner! It's by far the least endearing of the big Spanish cities. (Warner is also a pretty uninspiring park - and if you've been to a few Six Flags, you'll have been on near-clones of most of what they offer.) An infinitely better combo would be Barcelona and PortAventura - aside from their being both the best city & park in Spain, it's also brilliantly quick, cheap and easy to get from Barca to PA.

If you're set on a UK visit, and have been to London before, why not base yourself in the North or Midlands for your time here? Manchester is a culturally-vibrant city, York is utterly gorgeous (both are much more manageable in the small amount of time you're planning for than London), and Alton Towers is really the only theme park in the UK worth considering a visit to if you've got limited time in the country. (Unless you're a coaster obsessive, in which case Blackpool Pleasure Beach is a shoo-in.)

By "Astro Parc", do you mean Parc Asterix? It's a really underrated park, full of charm and a good mix of decent rollercoasters & the kind of odd dark rides you only really get in Europe. Whether it's worth a day away from Paris on such a limited schedule is questionable - though I suppose less so if, as you say, you've been to Paris before.

2 days is a pretty limited time to "explore Belgium and Holland". Dutch cities in particular really aren't a great fit for frantic sight-seeing - it's much more about the culture of ambling, drinking and savouring. If you've not already made arrangements, I'd recommend basing yourself in Amsterdam and renting a car for a day to get to Efteling. (Public transport is a bit of a hassle to the park if you aren't much of a Dutch speaker - and bus timetables there don't always allow you to stay for the whole day.) Of all your suggestions, that feels like the most feasible theme park day trip, assuming you are definitely committed to London in the UK.

If you'd like any off-the-beaten-track tips (London & Paris in particular), let me know. Whatever you decide, sounds like you're going to have an incredible time!

If you are only looking for a theme park to visit, then the simplest thing for you while in London is to go to Thorpe Park. It's not the best park in the UK, but it has a couple of decent coasters, and I'll ride The Swarm over The Gatekeeper any day. If you're lucky !! the Derren Brown ghost train might actually be working as well ... :) Get there when the park opens as it gets very busy mid-day on wards.
If you have the time, go to Alton Towers. The Smiler and Nemesis are both world class. 13 is one of a kind and not to be missed. And of course, the new Wicker Man woodie should be open too ? The setting of the park is really nice, with plenty of relaxing walks around the gardens. Where ever you end up, have a great time in the UK.