Dependents aren't required to have a number as part of the booking process but they do need to be under a visitor that has a mobile or landline number.
There are two ways to add a visitor as a dependent:
On your booking link
On the Zipline Management Portal
Adding a dependent via your booking link
While you're creating a booking with the booking link, you'll be asked for the total number of visitors that will be present for the visit (this includes the visitor making the booking). To create a booking with one standard visitor and one dependent, select two visitors.
You'll then need to complete the rest of the booking details for the first visitor.
The booking link will then ask for the second visitor's phone number. Instead of entering a phone number, click I'm booking for child or dependant. Then select a guardian/parent to attach the dependent to. The booking link will ask for the dependent's details to which you can add a new dependent or select a dependent's details that were previously entered by the visitor.
The rest of the dependent's details will be required as usual.
Adding a dependent via the Zipline Management Portal
Log into the Zipline Management Portal with your credentials. Once you've done so, make sure you're on the Visitor Bookings tab, then click Create Booking.
Fill in the first visitor's phone number and name. You'll notice a checkbox labelled Has dependents. Click the checkbox. From here you'll be asked for a First Name and a Last Name. You can type this in or select a dependent that had previously visited with the visitor.
If there are multiple dependents, click New Dependent.
Complete the rest of the booking details to finalise the booking with the dependent.