From San Jose, take a bus to Cartago. There are several buses every hour between 5 AM and midnight to Cartago from San Jose from Calle 5, Avenida 18. The fair is less than $1. From Cartago, take a bus to Santa Cruz. It will cost about $2.
From Santa Cruz, a 10 km (6-mile) road climbs up the mountain slopes. After another 4 kms (2.5 miles) along a rough 4wd road is the Volcan Turrialba Lodge. To get beyond Santa Cruz and to the lodge area, you will either have to walk, hire a taxi, or if staying at the lodge, you can arrange pick up. Contact the lodge at 273-4335 or 383-6075, or by email firstname.lastname@example.org. Their website is here. The lodge cost $40 (February 2004) and includes all meals.
Update: Apparently the lodge isn't very good in recent times and is over priced. This info comes from SP member Forjan. It now apparently cost $90 for two (July 2 2006) and is rather basic (but the food is good).
Volcan Turrialba's central crater
From the Volcan Turrialba Lodge, there is a very rough 4wd road that climbs to very near the summit. The distance is about 4 kms (2.5 miles). If you stay at the lodge, you can hire a nature guide or even a horse to get you to the summit, but of course since this is a mountaineering website, you should walk it. From near the summit, there is a picnic table and a trail around the crater. The route from the lodge is well marked and you can’t get lost.
Turrialba's west crater.
Take a jacket, raingear, and a camera.
If you have information about this route that doesn't pertain to any of the other sections, please add it here.
"Them, 1993: "Your climbing life is over when you get married". Them 2002: "Your climbing life is over when you have children". Me: "What a bunch of crap"."