It’s always great to find a walking alternative to the standard bus route and this is a beauty.
From the South, leave the bus at the stop in the centre of San Juan del Reparo and walk back to Calle Lance Padilla which is across the road from the church (Iglesia de San Juan Bautista). Follow this road to the end where it becomes the descending path with spectacular views to Garachico and beyond. At the end of the footpath; turn left onto Calle el Volcán and follow this to the path on the left which takes you into the centre of Garachico.
Spend some time wandering around this beautiful town then head towards the water front turning right towards the marina. Stay with pavement on the left of the main highway (TF-42) all the way out of town and up through the tunnel where you will find the Mirador El Guincho and views back to Garachico.
As you leave the car park take the road on the left (Calle Flandes) the short distance to where it meets Calle Camino Viejo on the right and follow this round and up to rejoin the TF-42 again for the short walk to Calle la Coronela on the left. Stay with this road, which becomes a cycle track, for 2km past the open banana plantations, all the way to the junction where the cycle track ends.
There is an alternate walk from this point to Playa de San Marcos: If you turn left on Camino Cuatro Caminos and follow this 500m to the crossroads turning left again to follow Camino las Barandas for another 500m down hill into Playa de San Marcos. This is a lovely little coastal town worth a visit with a beach and cafe/restaurants, there is also a Titsa bus service #362 which will take you up hill to Icod and runs every hour.
We however are going to continue our walk by turning right at the end of the cycle track onto Camino de Alzola and continuing up a steep hill into Icod de los Vinos; I would recommend following Calle de Hércules uphill to the park (Parroquia San Marcos) at the top where you will find a wide range of cafes, restaurants, shops and attractions in the area. Icod is a surprisingly lovely town of pretty squares and gardens well worth exploring and spending some time in.
When you are ready you can find the bus station half way down hill on Calle Francisco Miranda…if you need to wait for a bus, the café attached to the station serves good quality coffee and snacks and is very reasonably priced.