[1] The blockade of Arica was conducted by the Chilean navy's ships Cochrane, Covadonga, and an unnamed armed transport, all three having arrived by the 7th of December, 1879.

These defenses had a range of 3.5 km, providing a large covering zone for the remaining Peruvian ironclad, the Manco Cápac.

The now Chilean warship Huáscar, after its capture at the Battle of Angamos, had been sent for repairs and fitted with two 40 lb Armstrong type guns, with a firing range between 6 and 7 km.

At 8:30 am , the Huáscar approached the coast, near the island of Alacrán, to reconnoitre the state of the forts that defended the port of Arica.

As a result of this approach, the Peruvian defences of the Morro de Arica, under the command of Colonel Arnaldo Panizo, opened fire on the Huáscar, joined by the monitor Manco Cápac.

On the Chilean side, the Magallanes gunboat is also involved, which at the beginning of the engagement was 6 miles north of the port, producing an exchange of fire that lasts until 9:20 a.m. As a result of this cannonade, the Huáscar receives 3 hits without consequences.