Bus X60 travels to Mezairaa bus station from Abu Dhabi (Dhs30, 3¼ hours) via Madinat Zayed at 9am and 7.30pm daily. It makes the return trip from Mezairaa bus station at 5.10am and 3.10pm. Bus 660 shuttles between Mezairaa and Madinat Zayed bus stations (Dhs15, one hour) roughly every two hours between 8am and 9pm.
Taxis (no meter or taxi signage) wait at the bus station for passengers.
All the main roads are fit for 2WD vehicles, but you'll need a 4WD to go off-road.
Coming from Abu Dhabi, head west on Hwy E11 and turn south on Hwy E65 to Hameem or E45 to go via Madinat Zayed. The total trip is 250km either way. There are petrol stations on Hwy E65 at the Emirates National Auto Museum, in Tarif on Hwy E11 and in Madinat Zayed. In the Liwa Oasis, you'll find gas in Hameem, in Mezairaa, near the Khanur turnoff, and in Umm Hisin.
From Jebel Dhanna/Ruwais, the long and lonely Hwy E15 also goes to the oasis; petrol is available in Ghayathi.