Multi-city search functionality is not available in the Hopper app at this time. You can, however, search a series of one-way segments to make up a multi-city itinerary.
For One-Way flights:
On iOS and Android:
- Tap on the Search tab
- Choose your departure and arrival locations.
- On the calendar view, above Filters, you can select "Round Trip" or "One-Way" at the top.