We’re travelling INV-LHR-AUS next Thursday. This involves an overnight connection and terminal change. Arriving at LHR at 21:10 at T 5 and need to get to premier inn on bath road.
We’ll use public transport given costs of uber or taxi. Ive checked tfl journey planner and a couple of options, ie, 2 buses from T5 or tube to Hatton Cross then bus back to hotel.
Id appreciate any thoughts or input as to what might be most straight forward. We are elderly but mobile enough on our feet.

thanks in advance

Deleted as I didn’t know the 423 passed both Premier Inns!

423 Bus from Stand 7 outside arrivals, every 20 minutes until after midnight & Ł1.75 each.

Be aware there are two bath road Premier Inns but the bus passes both, if you are booked at the Premier Inn Named T5 its the second stop after leaving T5, the one named T2/3/Heathrow is about the 8th or 9th stop (Can't remember exactly which but someone will be along shortly to advise)

If you do go to the central bus station, it’s buses 105/111 which you need. They stop opposite the premier inn t2/3 (Oxford avenue stop).

In the morning it’s the reverse, so stop directly outside the premier inn and 105/111 back to the central bus station.

The 423 stop for the t2/3 Premier Inn will I think be New Road (stops at Harlington corner only on the way back) and then a 5 minute easy walk to the hotel, past Purple Parking.

To get to T3 the next day you use the stop just outside the Premier Inn T2/3 and one of the buses KARFA mentions. It’s very easy.

So just to be clear. It’s the 423 from T5 which goes to both Premier Inns and 105/111 to go to T3 (central bus station). I wondered if the OPs had bus passes issued from their local authority and if they worked on LTR buses?

I ask for a friend who is doing the same thing but routing from CDG. I advised the same hotels but I told her to go to PI T5. I was going to go back through the threads but you have saved me the trouble.

in case you're not used to London buses ... most drivers close the doors and pull away fairly rapidly ... so just make sure you take your seat as soon as you board the bus!
with the bus starting at T5 you will have a full choice!!

https://tfl.gov.uk/bus/timetable/423?fromId=4900164306

You need one debit/credit card per passenger. You cannot pay for a group on the same card.

From Premier Inn T2/3 to T3 any bus that takes you to Heathrow Central Bus Station will work, so in addition to 105/111 mentioned by KARFA you can add 278, 285 and 140 (and for very early departures N9/N140 are night buses, although that shouldn't affect you). There should only be a few minutes between buses.

If you are booked in the Premier Inn T5 then you have two options to get to T3 - either walk about 8 minutes and catch the U3 direct (simpler to walk to Pinglestone Close), or no walk then 81/423 to Bolton's Lane, cross the road (there's a lights controlled pedestrian crossing) then any of the buses above to Heathrow Central. You will need to touch in again on the second bus but if you use the same card you won't be charged as it'll be under an hour since your first journey started.

Allow 10 minutes to walk from the bus station to T3 departures - there are moving walkways. At the final stage you have the choice of a short escalator or lifts - unless you have a lot of luggage, the escalator will be much quicker.

I thought that I knew Heathrow and its surroundings but you have taken the biscuit! I think that if I was at Premier Inn T5 and had to get to T3 and it was a morning where there is constant moisture in the air as we are enduring here in Brittany; I would take the bus back to T5 and then the train to T3. The train is the nearest to the escalator/lift leading out of the tunnel to get to T3. Once outside there is no avoiding the elements to get to T3 itself but this is a lot less. I have never tried to get into the Virgin Terminal and walk through there, and do not know if one can do that. I may well try the T5 Premier Inn - the Thistle is such and sorry old flop house and the Sofitel is ridiculously priced.

That also works, but it will take a lot longer - not least because buses from Bath Road to Central Bus Station are very frequent, whereas there's less bus options to T5, then Underground trains onwards from there are only every 10 minutes (and Liz line even less frequent). T5, considering the single biggest operator at LHR is primarily based there, really is not at all well-served with public transport compared to T2/T3. There were probably reasons, but it always strikes me as a frustrating oversight that public transport is so poor to and from there given the emphasis that should have been put on it with a new-build terminal. The cynic might say that HAL gets to collect more drop-off fees as a result ...

You can do the journey using one of the two options I gave in about 15-22 minutes depending on which bus you catch (U3 will be quicker). By contrast, going via T5 then Liz Line/Underground will likely roughly double that.

By contrast, for going the other way - landing at T5 and getting to Bath Road - my instinct if with minimal luggage would be to get Tube/train to T2/3 and then pick up one of the many buses from Heathrow Central from there.

For Premier Inn T2/3: can you no langer get the Purple Parking bus to drop you at Purple Parking (next to the hotel) and vice versa?

I and others wouldn't call public transport at T% as 'poor' let alone 'so poor'.

T5 receives 50% of the tube trains that serve LHR - so one every 10 mins. Hardly a transportation desert.

Lizzie to T5 is 2 trains per hour which is 2 more than the previous Heathrow Connect service and more trains are limited due to the HEX services that take up the train paths that prevent any more Lizzie servicing servicing the airport. Hopefully that will change once HEX is no more (it's concession is due to end in 2028)

HEX won’t be going anywhere IMHO. The paths it uses aren’t any good for the Elizabeth line and GWR won’t want them either. HEX serves a market and with the Ł10/30 day tickets I’m back to using it over a crowded and slow EL service.