When traveling with children on Busan Metro, the ticket type matters. The operator's official table lists free travel with a child transit card or eligible mobile ticket for ages 6–12 in both zones, but a child QR single ticket costs KRW 700 for zone 1 or KRW 800 for zone 2. Zone 1 covers up to 10 km from the starting station and zone 2 is beyond 10 km. To qualify for child pricing with a transit card, register the child's date of birth through a convenience store or the card issuer; do not assume an unregistered card will apply the exemption. Buy QR tickets at station machines or use the Busan Metro app for mobile tickets. The operator notes that unregistered app users may be charged adult fares. Bus, Donghae Line and light-rail systems may follow different rules, so do not assume the metro exemption covers every mode.