Caleta beach (Playa de la Caleta) in April.
Caleta is our favourite urban beach in southern Spain, with calm, protected waters, soft sand and excellent facilites nearby. However, it is small so will be inevitably crowded in summertime. If so, hop on the #1 bus from nearby Plaza de España and take a 10 minute trip down to the massive beaches running beside and below Cadiz new town (photos below).
Playa de la Caleta seen from the San Sebastian causeway.