$189 Cheap Delta flights Philadelphia (PHL) to Tri-Cities (TRI)

Use the "Price (lowest to highest)" filter on Expedia to search for cheap Delta Air Lines round-trip flights from $287 from PHL to TRI. Affordable one-way options from $189 are available as well.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.

For cheap Delta Air Lines fares from Philadelphia Intl. Airport (PHL) to Tri-Cities Regional Airport (TRI), start searching one to three months before your planned departure. Securing domestic flights 34 to 86 days in advance could save you 25% compared to booking just 6 to 12 days ahead. The day you book can also influence the cost. Sunday tends to be the cheapest, while Monday is often the most expensive for domestic flights. You can save 6% on average by booking your journey on a Sunday.**Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.

Search Delta Air Lines's earliest flights from PHL to TRI by using the "Morning" and "Early Morning" filters. Not only will you get to where you're going sooner, early departures also experience 20% fewer cancellations.**Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.

With a rewarding loyalty program and an excellent in-flight experience, Delta Air Lines is the leading choice for many passengers heading from PHL to TRI. Also, if you're a Delta SkyMiles and One Key™ member booking with Expedia, you could earn OneKeyCash™* on eligible flights on top of your airline miles, which can be used on future travel purchases.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.