I spent 7 months in South America in 2013 including 3 month in Chile and drove the whole west coast from Arica in the North to Punta Arenas in Patagonia in a 4 x 4 with both kite and surf gear.
I took a 12m, 10m and 8m and kite surfboard, forget flat water the Southern Ocean never stops pumping. Up North I used the 12m and 10m a lot around Arica, La Serena Antofagasta, which was fun but nothing special wave wise.
Once you get down near the Santiago region everything changes, the wind, big waves, climate the scenery (you finally start seeing grass and trees after 2000km of Atacama Desert). Matanzas is the epic windsurf/kitesurf location in Chile, it’s a bus ride from Santiago but you really need a car. For kiting the best spot is a 2km downwinder (or 4x4 on the beach) to La Roca Quadrada . This is a fast sucky wave that goes and goes at 3m+ it’s dangerous. I was powered up on an 8m every day and blown off the water by around 3pm, most of the locals don’t have a kite bigger than 7m. At the main break in the village you will witness the best port tack windsurfing in the world (except perhaps the old Toomies crew in WA). Sit back with a Pisco Sour by the fire at the bar in Surazco after a hard day kiting and watch the show until it gets dark.
www.surazo.cl/ You can kite this main break but wind it’s way too fluky due to the big sand dunes and I never saw anyone do it just justice on a kite, myself included. If you have a car and surf, drive to a great left point break called Puetecillo and in the afternoon kite the next beach called Punta Topicanna which is more side shore wave riding. I found Wind Guru to be spot on wind wise, it’s either blowing or it’s not and once in the wind holds for about a week. Just check the forecast in Santiago and plan when to go but be flexible. For kiting only you have to go to Matanzas. (this isn’t a place for the inexperienced).
However if you have more time and like to surf I would recommend Pichilemu which is also a bus ride from Santiago. This is home to Chile’s best wave, Punta Del Lobos, an epic left hand point break that picks up everything the Southern Ocean has to offer. Surf in the morning and then kite in the afternoon at a break in town called Inferneo which is a big wall with fast sections on the inside but slightly onshore. You will be kiting alone except at the weekends. If the surf is massive the main break in town is fantastic fun just launch upwind at Inferneo and sail down 500m. Huge rolling walls perfect cross off direction that you can kite for over 500m, endless cutbacks. The problem is the wind in Pichilemu is much lighter than Matanzas even though as the crow flies it’s not far away. I used the 10m most days even the 12m some days. Pichilemu has a huge range of accommodation, shops, nightclubs and a great vibe.
Further south there are other great places but nothing to match these two. The water is very cold you will need a 4/3mm wetsuit, hood and booties but the benefit is great wind great waves and no crowds. Also you need to speak at least basic Spanish to get around once out of Santiago. If you have time and see a 3 -4m SW swell going up the coast (use Magic Seaweed) I would recommend a side trip to Pacasmayo in Peru. The setup is incredible with waves that break over 1km.
Patagonia is also incredible place have fun.