Paved (but long, winding, and sometimes potholed) roads connect Oaxaca City  with all regions of Oaxaca and neighboring states.
Four alternative routes connect Oaxaca City  south with the Pacific coast: Two of them, via Highways 175 and 131, connect directly south over the super-scenic but rugged Sierra Madre del Sur. Especially during the June–October rainy season, travelers are subject to landslides and bridge washout delays.
The longer but less rugged (and more dependable in rainy weather) route connects via Highway 190 southeast with Tehuántepec, thence Pacific coast Highway 200 west. The fourth route, also less direct, but still rugged and winding, connects west via Highway 190, thence south with the Pacific coast, via Highway 125.
Narrow national Highway 175 connects along 148 winding, sometimes potholed miles (238 km) with its junction with coast Highway 200 at Pochutla  (thence six miles/10 km to Puerto Ángel ). The road climbs to more than 9,000 feet (2,700 meters) through winter-chilly pine forests and indigenous Chatino and Zapotec villages.
Fill up with gas at the last-chance Pemex in Mihuatlán heading south and at Pochutla  (north edge of town) heading north; carry water and blankets and be prepared for emergencies. Under dry, daylight conditions, count on about seven hours at the wheel if heading south from Oaxaca City  to Puerto Ángel , or about eight hours in the opposite direction.
About the same is true for the paved National Highway 131 route south from Oaxaca, which splits off of Highway 175 two miles (three km) south of San Bartolo Coyotepec . On your way out of town, fill up with gasoline at the Oaxaca airport Pemex. Continue, via Zimatlán  and Sola de Vega  (fill up with gas again), over the pine-clad Pacific crest, a total of 158 miles (254 km) to Puerto Escondido . Under dry, daylight conditions, allow about seven hours southbound, or about eight hours in the opposite direction. Unleaded gasoline is regularly available mid-route at the Sola de Vega Pemex only.
Highway 190 connects Oaxaca City  southeast with Tehuántepec, along 155 miles (250 km) of well-maintained but winding highway. Allow about 4.5 hours to Tehuántepec (downhill), or five hours in the opposite direction.
At Tehuántepec, connect west with Highway 200, via Salina Cruz, to the Oaxaca Pacific coast, and Bahías de Huatulco  (100 miles/161 km, three hours), Pochutla –Puerto Ángel  (124 miles/200 km, four hours), and Puerto Escondido  (170 miles/274 km, five hours) via a paved, lightly traveled but secure highway.
The very long 229-mile (368-km) Highway 190–Highway 125 route connects Oaxaca southwest with coastal Pinotepa Nacional , via the Mixtec country destinations of Yanhuitlán, Teposcolula, and Tlaxiaco. Although winding most of the way, the generally uncongested road is safely drivable (subject to some potholes, however) from Oaxaca in about nine driving hours if you use the cuota autopista northwest of Oaxaca City  (exit to old Highway 190 at Nochixtlán). Add an hour for the 7,000-foot (2,100-meter) climb in the opposite direction.
The 350-mile (564-km) winding Highway 190–Highway 160 from Oaxaca to Cuernavaca, Morelos, and Mexico City via Huajuapan de León requires a very long day, or better two days for safety. Under the best of conditions, the Mexico City–Oaxaca driving time runs 11 hours either way. Take it easy and stop overnight en route. (Make sure you arrive in Mexico City on a day when your car is permitted to enter. See Mexico City Driving Restrictions  for the scheduled restrictions.)
Alternatively, you can cut your Mexico City–Oaxaca driving time significantly via the Mexico City–Puebla–Oaxaca autopista, combined 150D–131D, which, southbound, takes off from the southeast end of Mexico City’s Calzada General Ignacio Zaragoza. Northbound, follow the signs on Highway 190 a few miles north of Oaxaca. Allow about six hours driving time at a steady 60 mph (about 100 kph). Tolls, which are worth it for the increased speed and safety, run about $30 for a car, much more for a big RV.