We will be arriving in Athens on a flight (from Seattle, by way of Heathrow) due to arrive at 8 pm. We'd like to fly straight on to Chania, Crete, but the Aegean Airlines flight to Chania departs at 10:35 pm. Do you think it's realistic to plan this, given how much time it might take to clear customs, claim baggage, etc.? Our alternative plan is to stay in an airport hotel and take the 8 am flight to Chania the next morning. Thanks!
Normally 2.5 hours is enough for your connection time provided your London-Athens flight is not delayed for more than an hour.
In Athens there will be no customs control, only passport control since you will be coming from the UK which is now outside the Shengen area. Athens airport is not huge and easy to navigate, when you have collected your luggage just go upstairs to check it in for your Chania flight.
Note that with the Aegean App you can proceed with online check-in from 48 hours up to your flight departure time and that you should be at the boarding gate at least 20 minutes before the departure time of your flight.
Anyway, given that the flight to Chania will be the last flight of the day, in the event of a significant delay with the London-Athens flight you will have no choice but to stay one night in Athens, so personally I would keep this 10:35 p.m. flight even if it means changing it for a flight the next day in case I miss it.
The only hotel close to the airport (just opposite) is the Sofitel. The rooms are relatively expensive (at least 200€/night).
There is another hotel located in Rafina, about 20 minutes from the airport which is half the price and has a free Airport-Hotel shuttle . It's the Avra hotel.
There will be a customs control in Athens, but if you don't have anything to declare it won't take long.
I'd be looking at the history of the flights to see their on time record. I tend to be a "on time worrier traveler" and it impacts my state of mind when traveling especially with two connections. If it was me I would stay at the Sofitel ( expensive but oh so convenient and nice) on arrival and catch the first flight in the morning...somewhat refreshed and ready to tackle Crete... and most important stress free.
2.5 hours is plenty of time to make that flight, but if for some reason you are delayed long enough to miss it, as long as your flights are ticketed together with partnered airlines they are obligated to put you up in a hotel and get you on the next available flight to Chania.
It has been our experience that 2 hours has been sufficient to pick up luggage clear passport control depart arrivals level, go upstairs to departures, print baggage tags at the electronic machine, Drop off the bags (we always get our boarding passes 48 hours prior to the flight) go through security. Athens airport is very efficient. We generally have enough time for a Mythos beer waiting for the connecting flight.
While technically there is a customs declaration place it is actually a exit door that has a sign "nothing to declare" walk through the doorway and you are in the public arrivals level.
We had a flight from Vancouver delayed an hour due to a medical problem. Once in the air we arrived exactly on time . With a long flight like yours there is lots of time for the flight to make up lost time.
I can assure you that arriving in Chania after that long trip is way better than an overnight in Athens and a morning flight.
If your lodging in Chania is easy to get to and has late check-in, I would go there and get the traveling done.
Getting up for an 8AM flight ( 10PM 'body time') sounds ugly.
If I did choose to stay near ATH for the night, I would be looking at the 10-Noon time frame for a flight to Crete. My $0.02