At AGP, stay airside—busy terminals and long queues make short exits risky.
Take the Cercanias C1 train from the airport to Malaga-Centro Alameda (12 minutes, EUR 1.80). Walk 10 minutes south to the Paseo del Parque and the beachfront at La Malagueta. Spend 40 minutes on the beach and promenade. Walk back north to Calle Larios for 15 minutes of people-watching on the pedestrian boulevard before heading to the station.
Follow the beach route, then add the Alcazaba (EUR 3.50, 1 hour). The fortress is at the foot of Gibralfaro Hill, 15 minutes east of the center on foot. Book entry online if possible to skip the queue. For lunch, El Pimpi on Calle Granada is the classic choice for grilled fish and fried anchovies: mains EUR 14 to 22. It has outdoor seating in a historic bodega.
With 10 hours, take the train 5 minutes further east to Torremolinos (EUR 1.80) for a quieter stretch of beach. Alternatively, walk up to Castillo de Gibralfaro above the Alcazaba for views over the port and bay: the climb takes 30 minutes. Entry to the castle is EUR 3.50 or free on the last Sunday of each month.