Most people head down to the Avenida Maritima promenade by Alcaravanras beach to watch the yachts leave the marina. There's a great atmosphere as the crews all wave to the crowd and wonder whether they bought enough gin to last the journey.
Walk to the end of this jetty for the best view of the yachts leaving the marina.
However, to see all the yachts with their sails up, you need to be further south along the Avenida Marítima. San Cristobal village is a good spot as the race starts offshore and there are plenty of places to have lunch while you watch the yachts sail away.
For the best view of the yachts, head up the hill through old town Vegueta to San Juan. From the spine of the ridge that runs south from here, right by the ruins of the Bateria de San Juan, you get the classic view of the yachts at sail. The view from San Jose village on the hill above Triana is even better as you see the cathedral in the foreground. Head up Alameda de Colón street.
The ARC yachts start to leave the Muelle at 11.00 am and the main cruiser race starts at 13.00. The yachts, with their sails up and still clustered together, are visible for a couple of hours.