You can reach the Cañadas del Teide from all sides of the island.From the south there is a road from the airport via Villaflor to the Cañadas, from the West you must head for Chio either from Playa de las Americas or from Santiago del Teide. The northern road starts from Puerto de la Cruz and the eastern ascent starts from the capital Santa Cruz del Tenerife and crosses the mountain range Cumbre Dorsal.
Alternatively you can take the bus either from Playa de las Americas (Line 342) or from Puerto de la Cruz (Line 348). Both buses depart at about 9:00 a.m., the return buses go around 4:00 p.m.
The trailhead for the Roques de Garcia is at the Mirador los Roques near the Parador hotel. There is a parking lot and the busses stop at both locations (mirador and hotel).
The round tour starts at the parking lot of the Mirador de los Roques. Turn left (north) onto a fixed trail. You'll soon get to Roque Chinchado where you can take your signature picture. After that the trail - which at first was quite crowded - will become rather lonely with only few people on it. The trail rises to its highest point in the North of the Roques de Garcia. Look out for the Canary Lizards there: Blue - black and very large!
From the turning point the trail descends to Llano de Ucanca. The descend is very beautiful since it runs through some of the nicest formations of the group. Once on the bottom floor of the plain the trail heads more or less directly to "La Catedral" It offers nice views on Roque Chinchado from below and gets by the upturned plates of the signature picture. La Catedral is circled and it is here that the reascent to Cañada de la Grieta - the eastern side of the Roques de Garcia starts. You can go on to the last of the rock and then turn left onto the street but that street is very crowded and it is no fun to hike along it.
Better use the ascent route starting left (east) of La Catedral and return more or less directly to the parking lot at the mirador.
Normal hiking gear is sufficient. Many people try to do this round trip with running shoes but the rock (especially on te western part of the loop) is very rugged so that hiking boots are a good idea.