Details.
For ages 0 to 15, one child rides free per full-fare adult ticket, excluding discounted adult tickets. Additional children are 50% of a full-fare adult ticket, limited to two per full-fare adult, and further children pay the full adult fare. Children ages 12 to 15 traveling alone under the Unaccompanied Children policy pay the adult fare. Large school groups have separate pricing and policies. On the Portland, Maine to New York City route, one child up to age 15 travels for half the adult fare per full-paying adult ticket, for one-way or round-trip travel, and additional children pay the full published adult rate. Children under 16 cannot travel alone on that route.