navigating Gatwick

According to the Gatwick website if you're an EasyJet passenger you need to pass though Passport Control even though you are travelling with hand luggage only,

https://www.gatwickairport.com/at-the-airport/flying-in/flight-connections/

And yes there will also be security.

Thanks for the reply! I only have 1 1/2 hours to make connection. I see that I can purchase something from the airport itself that gives me access to both passport control and security express? Ever heard of that? Seems well worth it if it helps speed things up.

I would be concerned with such a short gap between flights plus the risk of your inward flight being delayed. Sorry, but there is no way that I would attempt to get from Portugal to London on the same day for an onward flight that isn’t a protected through ticket. Stay in London the night before your homeward flight.

I use EasyJet a lot at Gatwick, but sometimes, like all airlines, they can be delayed. My evening flight last week with them was running over an hour late.

One of the things I would do is make EasyJet aware that you are connecting prior to your flight... are you booked on one ticket all the way through to Seattle or are both booked separately? If separate then you will have challenges especially if you are delayed, if you are not delayed then you should be okay but it is tight and you will definitely have to go through security and if you can get a fast pass through then great. However, personally I wouldn't put myself through it especially if you are on a cheap ticket to Seattle as if you are late for the flight it may not be as simple as just getting them to put you on a later one, they probably will charge you for a new ticket - at least they are well within their rights unless you have a flexible ticket. Personally, I would move the Portugal flight forward. I think this is what you are talking about in terms of fastpass - but it relys on your flight being on time, or even better early.

I agree with the others 1½ hours is not enough time, even with the two flights being in the same terminal.
You will probably have to go through UK entry passport control, then exit again to catch your second flight. Either way you will have to go through security to get to your second flight.
North Terminal is big, some of the gates are signposted as 15 minutes walk from the waiting area.
What is the minimum check-in time for your second flight?
Easyjet may be late, and has no responsibility if you miss your second flight.

Is this a morning or afternoon connection? Flights are more likely to be late in the afternoon, as any delays during the day will be cumulative, and budget airlines like Easyjet have short turn-around times with no spare time to catch up, if a plane gets delayed, it runs late for the rest of the day.

Traditionally, easyJet has not connected to any other carrier. There was some movement to expedite flight transfers, and Westjet was included in the discussion. But I cannot find any indication on the easyJet website of what became of it. Perhaps readers with recent experience can comment.

Anyhow, I also cannot see any Westjet flight that goes to Seattle from Britain, or from anywhere.
In your place I would be in touch with the airline or airlines directly.

Norwegian flies Gatwick to Seattle (amongst many other places)
Westjet flies Gatwick to Canadian locations only: Calgary, Toronto–Pearson, Seasonal: Edmonton, Halifax, Vancouver, Winnipeg
See here: https://en.wikipedia.org/wiki/Gatwick_Airport#Airlines_and_destinations

Perhaps the OP could clarify.

Just as a FYI reply to Southam's mention of easyJet connections - they do have some special partner arrangements with other low-cost carriers for long-haul customers (including Westjet and Norwegian), but only if you book as a single ticket (for example through their "Worldwide by easyJet" site https://www.easyjet.com/en/worldwide)
If you book this way and are going via Gatwick, you automatically get the GatwickConnect+ Bundle service included, which includes premium security line access and reprotects you if your inbound flight is delayed or cancelled. However, their schedules are based on a 2 1/2 hour minimum connection time (see website http://www.easyjet.com/en/help/extra-services/worldwide) so I am guessing the OP didn't book this way? In that case, the Gatwick "premium passport" option might help guarantee a quicker transit, but as has been mentioned, only if your flight is on time (and it's still a bit tight even then).

Thank you all! Such words of wisdom are appreciated. My London-Seattle Westjet flight is with frequent flier miles from Delta. Delta is partners with Westjet. I used the miles for the Westjet London-Seattle piece (lay over in Vancouver) and purchased a separate Easy Jet from Lisbon to Gatwick so no protection there. I had 3 hours to connect in Gatwick to Westjet-plenty of time. However! Westjet upped the departure time from London and gave me a lovely 4 hour lay over in Vancouver resulting in the 1 1/2 hour connection time in London rather than the 3 hours I had planned. Delta will give me a full refund and redeposit the miles and tried to help re-schedule. I'll keep looking but will heed your advise and not try that short transfer time in Gatwick. I absolutely love Norwegian but using those miles was too tempting-especially when it looked like I would not have to spend the night at Gatwick.