But the border now closes at 10pm, or 11pm according to some Khmers ( I can confirm it's definitely open until 10pm, not sure about the latest 11pm claim). However, by arriving that late you'd have to organize a taxi rather than a bus as I doubt there would be any bus services at that time, but it can be done. However, even if you rush, a 7pm arrival at the airport is just a bit too late to make it across the border the same day. If it was 5 or 5.30pm and you caught a connecting bus from the airport to the rong kleua market (if they still operate at that time) or a taxi it would be possible as it only takes around 3 hours. However, at 7pm forget it because by the time you've collected your luggage after passing through immigration and then customs it will easily be 8pm.
11

clairy
Hi I did the journey using the state bus and it was really easy. Happy to report tht we didn't get scammed at all!
Pro tip