My girlfriend and I are looking to get a cab early (6:00-6:30 AM) on a weekday to Suvarnabhumi airport from lower Sukhumvit. What’s the quickest route via taxi? Should I ask the driver to avoid the route where you pay tolls? What’s a good way to make sure that we get a metered taxi? Should we ask our hotel to arrange it for us or should we hail it outside and away from the hotel? The Airport Rail Link/BTS wouldn’t work for us because we’ll have some luggage which would make it quite convenient.  Any helpful tips would be much appreciated. 

Yes ask the hotel to get a taxi.
Mention you want it on meter.

That's right. Ask the hotel to call a taxi for you. At that time, you should be able to avoid traffic. They will most likely use an expressway entrance near the area and go through the pay tolls, which makes it faster.

its about 200 baht on the meter , less than 100 baht extra in tolls

 

its going to be hard to get a taxi that wants to use the meter , since you have luggage you cannot just stand on Sukhumvit and hail any cab....

 

Also figure out how they are going to get on the expressway ,  if you are on odd numbered Sois they are going to need to do a U-turn to get back to the Expressway at Soi 1

 

Nornally they will take 400 baht  and not use the meter , 

 

no matter what its still CHEAP

I would use grabtaxi instead.

For anybody reading who is not in a hotel, you can dial 1661 yourself and order a taxi in advance.  If you do it the night before, you will get a confirmation call in the morning with the license number of the taxi.  If you are booking for a ride at the time of the call, they will give you the license number on that call.  There is a surcharge (B25? B50?) to reserve a taxi this way, and they will use the meter.

Uber.... will come to your hotel and be a nicer vehicle. About the same price as a metered cab, sometimes around 10% cheaper. 

 

I think you will find that the airport rate for UberX is rather expensive at 450 baht + tolls, but it would guarantee you a ride in a decent car.

 

One more option is AllThaiTaxi. You can phone them or use their smartphone app and book a taxi in advance for 100 baht. You journey will be by the same meter rate as a normal taxi, but you will get a very nice Prius and a professional driver. Note that AllThaiTaxi drivers are not permitted to exceed 90 kph on the highway.