Bilbao follows the Nervión estuary from Casco Viejo to the Guggenheim and San Mamés. Pick the old town for pintxos and narrow streets, Abando for rail and shopping, or the riverfront for museums and walks.
Casco Viejo is built around Plaza Nueva, Santiago Cathedral and the riverside Mercado de la Ribera. Seven old streets lead toward the Arriaga Theatre. The bars around Plaza Nueva stay lively after dinner, so a room facing an inner courtyard can be quieter.
Across the river, Abando has the main station and Gran Vía. Walk west along the estuary and you reach the Guggenheim Museum and the riverside paths of Abandoibarra. The tram connects the museum with Abando and San Mamés.
Indautxu has restaurants and shops around Plaza Moyúa. Continue west for San Mamés stadium and Bilbao Intermodal. Across the estuary, Campo Volantín leads to the Artxanda funicular and a high view over the city.
You can walk most of Bilbao along the river, but expect wet days even in summer. The metro and the tram run different routes. Check which stop is nearest the hotel, because a riverside address is not always near a metro station.