T3 Access with T5 boarding pass
 

Apologies if this has been discussed before (searched and couldn't find anything) but if I hold a BA First boarding pass that departs from T5 at LHR (I'm originating in LHR and hold a British passport). Is it possible for me to spend some time in the CCR then go over to T3 (I assume by simply leaving the terminal and going over to T3) to use the Oneworld lounges over there for a bit? Will likely have 7hrs at LHR so plenty of time but not sure on feasibility of entering T5, leaving, then entering again.

Thanks in advance!

T5 to T3 and back is possible. Question would be why? I would just stick with the CCR even if it is for seven hours.

You can't just leave T5 and enter T3 like that, a T5 boarding pass won't get entry to T3 via landside. You have to use the transits to T5C, come back to T5A, go airside to T3, clear security, return via airside transfar, renegotiate your Ready to Fly Status, hope you keep your seats in the process and then reclear security. Mostly you would be mad to do this, when there are many easier options open to you.

This is possible but tricky, as you will have to approach BA on your return to T5 to have your boarding pass "Ready to Fly" status cleared before it can be scanned at Security.

Thanks corporate-wage-slave and dakaix for that, definitely did not realize it was as complicated as that! Guess i'll just have to "put up" with the CCR haha!

Remember you'll have a choice of CCR, GF, GC South, GC North, GC T5B, plus the spa (5A South or 5B). Not worth the hassle of transiting to T3 and back. Think of all that wasted time in queues when you could be eating and drinking!!

Another tricky thing: the QF, AA or CX may refuse you entry with a T5 boarding pass.

Lounges bill the entry fee to either the FFP or operating airline.
The operating airlines/FFP may refuse payment if the passenger accessed a lounge in a different terminal.

We have such a situation in MUC. TK flies from T1. The Lufthansa Lounges are in T2. These lounges turn away eligible pax, who are departing on TK.

I appreciate the situation may differ elsewhere, although while there's always a small risk there is precedent here.

I have accessed the T3 CX lounge on a T5 ticket several times in the recent past, but only when I was already in the airside connections flow. I've exited T5 from airside before (for other reasons) and experienced the fun with getting the Ready to Fly flag corrected, it's not something I would recommend lightly... especially given the issues a non-BAFTer would have finding a sufficiently knowledgeable ticketing agent at Check-In.

Not trying to thread-jack here, but I'll be arriving on a CX flight at T3, connecting to a T5 BA flight 7 hours later. I'd prefer to spend some time in the T3 lounges and then airside transfer to T5. On arrival at T3 can I simply follow the signs for T3 connections and convince the staff to let me enter the T3 departures area to access the lounges? FWIW I have an Admirals Club membership.

Hi.

That should be possible. I assume you have lounge aceess for t3 lounges. I did that last November. Remember to allow plenty of time for the T3 to t5 bus transfer and security when heading to t5

Regards

Tbs

HAL Security will permit you to enter T3 at the Connections screening point if you're in possession of a valid boarding pass for your onward flight, and for the specific purpose of using the shops & lounges. After you've finished in T3 you'll need to use the airside exit route to return to the arrival/connections flow in order to head to T5 - I would say no later than 2 hours before your onward flight, as the buses can get busy.

See KARFA's guide below, albeit you'll be following it in reverse:
https://www.flyertalk.com/forum/29998308-post383.html

Second this advice.

There can be very good reasons to go to T3, eg QF and CX lounge access for their own FF allows more guests (DM on CX gets 2 F guests) etc...

Follow up: I just did a T5 to T5 (BA-BA) connection and used the automated gate/electronic boarding pass reader before security. If arriving at T3 and following the T3 to T3 connection path with a T5 BP, is there a similar automated BP reader in T3? Do I need to bypass this somehow by speaking to an agent? How does this affect conformance/ready to fly?

I think there is but not in the fasttrack lane. Also sometimes those readers don’t let your go thru even with valid BP

If you arrive airside in T3 and your next flight is T5 then yes you can use T3 Flight Connections without problems. You boarding pass may not scan, but just say you are going to the lounge (or shops) and that will be fine. Then eventually when you get to T5 your boarding pass will be OK at the gates there, so no issues T3 and T5 are on completely different systems so it can't really be compared to a T5 to T5 connection, however you would have been free in that situation to go to T3 first and then on to T5. Note that you cannot count on access to the Cathay lounge since recently they have turned non Cathay passengers away due to overcrowding in the 2 hours or so before their flights.