Two Weeks in Netherlands and Belgium without Car

May is too early for beach going. Most beach-going structures will be still pretty much shut down until the last week of May or so. Water is likely to be very cold. This being said, water sports are possible even if lying on the beach tanning and swimming are not good for. The whole Dutch coast is windy. The most accessible beach towns without car are Zandvoort and Hoek van Holland - both can be visited as day-trips with direct train access. There is also an urban beach in DEn Haag called Scheveningen. It is a suburb of the city (sort of), accessible by tram from Den Haag train station. If you have this time in the Netherlands in May, I highly recommend that you check out (and see if that is your cup of tea or not) two attractions that are on their prime during that period: the Kinderdijk windmill natural park and the Kroller-Muller museum in the Veluwe National Park. In Belgium, you can surely get a "taste" of these places in that time. I'd however pick either Ghent or Antwerpen for a stay and couple that with a stay in Bruxelles (you can visit the other city by train as day-trip). Consider a day-trip to Namur as well to visit the citadele.

On my most recent trip to the Netherlands, I decided to stay in The Hague instead of Amsterdam and I really enjoyed it. The hotels are considerably cheaper and there's a lot to see. It's also easy to day trip to other Dutch towns - Delft is charming and just a short tram ride away. So I'd suggest you split your time between The Hague and Amsterdam. The Hague is as easily reached from the airport as Amsterdam - only about 5-10 minutes more on the (frequent) trains. On the same trip I stayed in Ghent. I think you could easily base there and see Antwerp and Brussels as day trips.

I love the picture-perfect town of Domburg on the far end of Zeeland, but it probably isn't easy to reach by public transportation. If you wanted to give the coast of Belgium a try, most of the towns there are easy to reach by train and tram. The two biggest are Oostende and Blankenberge, but my favorite is De Haan. As Andre noted, May is too early for any aquatic activities, but the towns should have some activity going on. "Mostly interested in visiting museums, churches, microbreweries or bars with good local beers on tap" Get your beer fix at a restaurant, not a pub. Restaurants usually carry better beers and larger selections. My experience with pubs in Belgium is that they usually have an unremarkable cheap pilsner on tap, like Jupiler, Primus, Cristal or Maas (no better than the mass-produced stuff watery stuff brewed in the US), and perhaps a few better beers in bottles, like Duvel or Leffe.

Because there have been a lot of threads on questions like yours lately, I'd suggest you type "Amsterdam Brussels" or "Belgium Netherlands" into the search box at the top right. Forget about the beaches. I went to Osteende off-season, and it was dull and mostly reinforced-concrete beach towers. I had a mission, the (dead) painter James Ensor, but otherwise it's just a chance for good seafood off-season. Make sure to get to Keukenhof before May 20. Consider spending some of your Amsterdam days in Antwerp, which is (opinion) a more sophisticated Amsterdam - although the painting museums are better in Amsterdam right now. But there are good museums and better churches than Amsterdam in Antwerp.

@Tim: the Dutch coastline is completely different in respect to your experience in Oostende. Most of it has dunes and only in Scheveningen there are high buildings near the coast.

The new Rijksmuseum in Amsterdam will open April 13th after being closed for 10 years (except one wing). Be sure to reserve your tickets in advance, because even the natives are going to want to see this renovated space, and it is bound to be jammed the entire spring and summer.

I have never been to Amsterdam, but a small version of Amsterdam called Delft was amazing. Delt if famous for it's blue and white pottery and dishes. Close to Delft is 19 windmills at Kinderdijk, absolutely gorgeous. Knokke is a cool little town with a hideous beach. We spent 3 nights in Ghent and felt one was enough. Beware, Ghent is much muhch larger than Brugges. Brussels is worth about 2-3 hours, the Mannekin Pis and the Grand Place. Not worth seeing IMO. You will love Holland and Belgium!

Thanks for the tips about the beaches, other towns to consider as alternatives, and for the advice on the museum!

While I agree that Brussels is overrated, since the OP mentioned museums, it has to be mentioned that you could spend a full day just going to the four best art museums: Modern Art, Ancient (i.e. not-modern) Art, Magritte, and Bozar. They're very close to each other. And while the KMSKA in Antwerp is closed for renovation, this is the best "on the walls" of Belgium. Although I like everything on display, you'd be sorry to miss "The Death of Marat", wouldn't you? Even if it's pouring rain, then you have the Coudenberg (slickly redone, Charles V palace cellars) and the history of Belgium museum, BELvue, and the Musical Instrument museum just steps apart. And by ducking through the nice old Ravenstein arcade, you can get back to the Central Station almost dry.