For a reliable car service go to the web sites of Dial 7 or Carmel - they are the largest in the city. Do understand that the price they quote you is plus the returning tunnel toll and a 20% tip. But it should be more in the range of $100 than $180.

They can best advise you what time you need to be picked up - based on traffic conditions - which can vary a lot depending on day of week, time of day, time of year, weather, construction etc.

I would check with your airline as to what time to get to the airport. For international flights many airlines what you there 3 hours in advance (since check in lines can be very long and I'm had security take more than an hour). So you may need to be there at 4:30.

From downtown I would assume an hour would be plenty of time - but on a particular day it might not be based on conditions.

We've used Carmel a couple of times between lower Manhattan and EWR, and have never been disappointed by the service or the price. http://www.carmellimo.com/Rates.shtml

I would ask the car service about the best pickup time; I certainly would allow two hours, hence leaving the Battery around 3:30 - 4 at the latest.

I use Dial 7 myself, but I've also used Carmel and both are reliable. I believe the trip to EWR is $80 all in (toll, tips, etc.). It might be $85 now that the tolls and taxi fares have gone up and have been matched by the car services.

As for timing, you'll go through the Holland Tunnel, and the trip will take between 30 and 60 minutes depending on the traffic. If you have an international flight I'd leave no later than 3:30 (4 hours before). Just be aware that it can take a considerable amount of time to get into the tunnel if you have bad luck with traffic. It once took my in-laws 60 minutes to drive from the Brooklyn Bridge to the Holland Tunnel on a Saturday afternoon. But that's unusual, and since you are below Chinatown, you'll miss the bulk of the really horrible traffic.

You can also ask the car service what they recommend.

Depending on how close your hotel is to Penn Station (NYP) the NE Corridor train #127 weekdays or #163 weekends leaves for EWR at 4:05PM and arrives at the EWR train station 22 to 25 minutes later. You show your that day Amtrak receipt/ticket to EWR to get on the monorail to the airport terminal. The fare is $25/per person Monday through Saturday (advance purchase). The Sunday fare seems to be $52 per person. You have to be able to move your luggage by yourself and there is no tipping involved.

If anyone is going to EWR by train it makes no sense to take Amtrak. Take NJ Transit from Penn Station (usually $12.50) and then transfer to the Airtrain monorail. That is often faster than a taxi, but from the financial district I'm guessing a taxi will be faster (potentially 30 minutes as opposed to 50 to 60 minutes on the subway/train), just three times as expensive. If the OP has luggage, then it's not a bad trade-off if they can afford the car fare.

I may be in a minority, but having been stuck in traffic, including lines for the tunnels for up to 45 minutes and more, I just feel safer taking the train (NJ Transit). For me it's not a matter of saving money to do so, it's just that I can't stand biting my nails worrying about making a departure time while sitting in a car in stopped traffic.

By the way, not too long ago we sat in our car inching toward the Holland Tunnel for over half an hour -- and that was on Sunday evening around 5:30 -- we couldn't figure out why the traffic was so bad on a Sunday.

NeoPatrick, I agree that often the train can be less stressful. The problem is that since the OP is staying near Battery Park, it involves an inconvenient subway ride up to Penn Station or a taxi ride there. If there's traffic to get to the tunnel, there may be traffic from Battery Park to Penn Station. Then you have to add in catching a train at a certain time (less frequent on weekends)or wasting time at the station, and the train scenario becomes just as much of a nail biter!

I just allow more time than I think it will take to get to the airport. I'd rather roam around the terminals for an extra 30-60 minutes than worry about cutting it too close.

Baased on where they're staying - getting from the hotel up to Penn Station in time to get tickets and manhandle luggage down to the platform could easily use up any potential savings in time - as well as being a PIA.

Agree traffic can be hideous - that's why to call the car service. They ahve cars going back and forth to the airports constantly and know all the conditions.