You don't need to get separate paper tickets to transfer across companies, but you do need to get a special transfer ticket, which can be complicated. The good news is there's really no reason to deal with them these days, just get a Suica/Pasmo card and tap on/off.
The one complication is that there are extensive through services, meaning companies running on each other's tracks. This is super convenient, because it avoids having to transfer, but can be confusing. You can board a train in the Yokohama Minatomirai line and travel smoothly through the Tokyu Toyoko, Metro Fukutoshin and Tōbu Tōjō Lines to emerge right on the other side of the metropolis.
I passed through visiting old friends last week and they had them at some stations but not all.
But it was never a problem to get one at the airport, which where a vast majority of people should get them.
If you skipped that part, it was quite painful in the past few months because of the IC chip shortage.
And I think recently when you look up directions in Apple Maps, it even suggests adding a transit card if you don't have one!
Here, under Transit Cards in Maps. https://www.macrumors.com/guide/ios-16-maps/
It would be a _fantastic_ feature if I wasn't a control freak and didn't add one before I even boarded the plane, but still a very nice touch.
Tourists should get a physical card at the airport. There are too many caveats and exceptions to phone wallet support for non-residents.
> Sales of JR East's Suica card (image of a penguin on the front) will be discontinued for the time being as of June 8 due to a worldwide semiconductor shortage. [1]
Welcome Suica (for short-term visits):
> Welcome Suica sales will be limited to the following for the time being from December 18th:
> * JR EAST Travel Service Center, Haneda Airport Terminal 3 Station
> * Welcome Suica exclusive vending machine, Tokyo Monorail Haneda Airport Line Haneda Airport Terminal 3 Station
> Please note that only one Welcome Suica will be sold per person.
> Please note that IC cards will not be sold at Narita Airport after the 18th. [2]
PASMO:
> The sale of blank PASMO has been temporarily suspended.
> The sale of Personalized PASMO has been temporarily suspended. [3]
PASMO PASSPORT (for short-term visits):
> The card is available for purchase at 21 locations. [4]
[1] https://www.jreast.co.jp/e/pass/suica.html
[2] https://www.jreast.co.jp/multi/en/welcomesuica/welcomesuica....
Paper tickets are confusing but basically nobody uses them. I don’t think it’s true that you need to get separate tickets for separate train lines. You do need to adjust your ticket if you prepaid the wrong distance.
Unless you mean two entirely separate lines separated by different gates.
I don’t know many who ride that line unless living out on it or wanting to take the less crowded way to ‘Baba tho.
Because it's not just one company.