Connecting times in EWR for international to domestic using separate airlines

It's hard to determine the minimum connection time without a few more details. For the sake of argument, I'm going to assume you're flying JNB-EWR on UA187, and that you're asking this because you are considering booking two separate tickets. Also for the sake of argument, I'm assuming that you're then planning on doing DL4471 to MSP and then connecting onward to BOI.

The standard connection time between different international to domestic airlines at EWR is 1.3 hours, and for UA in particular it's 2.3 hours. These are the minimum times that would be required to put you on the same ticket.

Consider that a flight boarding at 7:55AM is going to try to push back at around 7:25AM, and may release your seats before that if you're not at the gate. Also consider that UA187 is only on-time around 77% of the time, with an average of delay of 18 minutes and a maximum delay of up to 1h 29 minutes. That might leave as little as 45 minutes optimistically to deboard, clear customs, clear security and board the next flight. You'd miss the flight completely in the pessimistic case.

It looks like as of right now, that flight arrives into Terminal B, which is the same terminal that Delta operates out of in Newark, so there's no Airtrain/terminal change involved, and you can try to reserve a spot to get through security faster with the Newark VirtuaLine program. (Again, assuming you're trying to connect on a Delta MSP flight)

It's probably possible, but I wouldn't book it in your situation. I have global entry and am pretty familiar with that airport, but it's pretty tight. I'd leave at least an hour and a half (if not more) for that. Ideally you want to book this on a single ticket so that UA is on the hook to get you to BOI, even if there is a misconnect.

Assuming that you decide to book this anyway and don't make it, Delta may accommodate you under the Flat Tire rule, but it's really up to the agent. I'd be prepared to pay the full cost of the onward fare (possibly minus what you paid for that ticket) if you are unsuccessful.

That depends on the details. If this on the same ticket (regardless of airlines) and you have global entry, than this should be fine.

I would not recommend this for separate tickets. Wait times at immigration and security are hard to predict. You can check past performance here: https://awt.cbp.gov/ . Global Entry and TSA PreCheck certainly speeds things up, but they are not always open or available.

If you miss the connection on separate tickets, you count as a no show for the second one and may have to buy a same day ticket on the spot (which will be expensive).

It depends on many things, so it is high-risk.

• your plane might arrive late
• if you sit in the back of the plane, you need 15 minutes at least to get out
• if there’s a long line at immigration you’ll have to wait easily 15 to 30 minutes / if you have global entry or such you might be through in five minutes
• Customs is normally zero seconds for walking through, but if they pick you out you might spend another five minutes there
• changing terminal and gate depends on your walking speed, could be 10 minutes, could be 30
• clearing security again could take a minute or much longer (again global entry helps) [thank @Hilmar for the reminder]
• boarding closes at least 10 minutes before the flight leaves, so you have to be there earlier

Adding this all up, you might or might not make it…

Personal experience, I need 30 to 40 minutes between plane-at-gate-and-doors-open and being at the departure gate; but I know the airport well, have global entry, and walk very fast.