Constanţa is Romania’s largest and most important port city on the Black Sea; in summer, it's also the gateway to the country's seaside resorts. Accommodation here is cheaper than in Mamaia and maxi taxis cover the journey in about 15 minutes, so it may be worthwhile to consider basing yourself here even if you’re only coming for Mamaia’s beaches and discos.
After passing through several countries and absorbing countless lesser waterways, the Danube empties into the Black Sea just south of the Ukrainian border. The Danube Delta (Delta Dunării), included on Unesco’s World Heritage list, is one of Romania's leading tourist attractions.
Mamaia, a thin strip of sand extending north from Constanţa, is Romania's most popular and expensive beach resort. In season, from early June to early September, the 8km-long beachfront is lined end to end with sunbathers from all around Romania who compete for that precious patch of seaside real estate.
First recorded in the mid-14th century by Visconti, a traveller from Genoa, the remote seaside village of Sfântu Gheorghe retains an ever-so-slight alternative vibe, fed by the town's lovely, lonely beach and its sleepy, noncommercial core. It's also one of the best places in the delta to sample traditional cooking (including some fabulous fish soup).
If you've got time for just one Romanian resort, make it Vama Veche. While it lacks the polish of Mamaia and has fewer services, it's smaller, more relaxed and more rustic. Under the old communist regime, 'Vama' enjoyed a reputation as a haven for artists, hedonists and free thinkers.
The sleepy fishing port of Sulina is Romania's easternmost point and the highlight of any journey along the Danube's central arm. There's a beautiful, tranquil (during the day) beach here as well as a charming canal-side promenade. It's also an excellent base for forays deeper into the delta or on to the Black Sea.