Splitwise
Log ferries, tavernas and taxis as you go, then settle up once at the end instead of doing maths at dinner.
Holafly
Buy a Greece/Europe eSIM before you fly and activate on landing — keeps maps, ferry apps and this trip app online without roaming charges.
Wise
Hold AUD and EUR in one card, convert at close to the real rate, and pay in euros without bank markups. Top up before you leave.
Qatar Airways
Check in, hold both boarding passes, track the Doha connection and get gate or delay changes straight to your phone.
Tip: create the Splitwise group and buy the Holafly eSIM before departure — both are fiddly to set up on airport wifi.