The 3 most popular way to travel between Dubai and Abu Dhabi is via driving yourself (an hour drive), getting a cab (around 240 AED), or via the bus (25AED). I’ll, of course, be covering the cheapest way to travel, and also a little tip for the cab option if you’re feeling lazy.
Even if you’re traveling via bus, the journey possibly averages at around 2hours (not including possible traffic jam). The bus would get you between the Ibn Batutta Mall (Dubai) to the Abu Dhabi Central Bus Station/Terminal.
You’ll be charged via the Nol Card regardless of directions so do take note of that. (Even if you’re going from Abu Dhabi to Dubai, you’ll have to buy the Nol card instead.
E101 that would bring you to the Marina area of Dubai, and also the E100, which brings you to the Deira area of Dubai. In any event, if you’re unsure, there is the information counter and also feel free to put on your location you wanna go on Google maps, the driver would advise you on which to go. The bus services run from 5:00AM to 10:00PM. Oh and there's also a USB port for you to charge your electronics along the way!
I haven’t seen much of the cab drivers approaching people in Abu Dhabi, but however if you’re traveling from Dubai, upon reaching Ibn Batutta Bus Station, there would be cab drivers asking around for people who want a cab ride. The catch? You’ll split it 4 ways with other passengers so it’ll only set you back at around 60AED. The additional catch is that the fee would cover the ride to any location (as long as it’s reasonable) around Abu Dhabi. So you maybe could consider this option if you are traveling with baggage and if you’re lazy to go around via bus with that awkward backpack.
This is a pretty neat hack because there are cloakrooms in most attractions around Abu Dhabi, so you could probably just take a cab ride straight to the attraction and have fun before going to your accommodation, instead of going to put your stuff at the accommodation before heading out again.