With some of the best waves along the Atlantic coast, Necochea is a hit with surfers; it also attracts windsurfers year-round. At the north end of the town's wide beach are picturesque dunes that roll along the coast until the industrial port begins at the river mouth. Given the presence of the port, pollution could be an issue here.
Speaking of the Río Quequén Grande, there's easy rafting and kayaking upstream, particularly around the falls at Saltos del Quequén. Local outfitters organize both river and ocean kayak trips in summertime; just take a stroll downtown to see what's on.
The dense pine woods of Parque Miguel Lillo, a large greenbelt along the beach, are popular for cycling, horseback riding, walking and picnicking. Horses and bikes can be rented inside the park.