Can we just swipe the same card 3 times while going thru the gate? You need 3 cards. Every individual needs their own cards to use train. Scanning the card three times to allow three people, or giving the card back so three people could use it would not work because of the design of the system.

Yes, every individual traveler in Japan must have their own Suica card (or equivalent IC card like Pasmo or Icoca). You cannot "tap" one card multiple times to pay for a group of people at a train station or on a bus. This is because the Japanese transit system is based on an "entry and exit" record; the gate needs to record the specific starting point on a single card and then calculate the fare based on where that same card exits. For families traveling in 2026, children aged 6–11 can get a specialized "Child Suica" which automatically charges half-price fares, but this requires showing a passport at a JR ticket office for age verification. For most 2026 tourists, the easiest option is to use a Mobile Suica on an iPhone or Apple Watch (via Apple Wallet), or purchase a Welcome Suica at the airport, which is a specialized 28-day card designed for visitors that requires no deposit fee and features a distinct cherry blossom design.