Flight Deals from San Francisco to Boston from $141

Flights from San Francisco to Boston are cheapest from early January to mid March and most expensive from mid June to early August, with December being the peak month for prices.

When planning your flights from San Francisco to Boston, you’ll notice significant price fluctuations throughout the year. Generally, the most expensive times to fly fall between mid June and early August, with peak prices especially high in late December. Conversely, the cheapest period tends to be from early January to mid March, where prices can drop significantly. Notably, late December marks the highest price point, while mid January features the lowest. Be aware that the transition from low to high season is quite abrupt after March, so booking early can save you money.

Book tickets from 29 to 35 days before departure for the best rates from San Francisco to Boston.

For your trip from San Francisco to Boston, the best time to buy tickets is between 29 to 35 days before departure, as prices are lowest around 33 days out, generally ranging from $333 to $540. Avoid booking earlier, since prices can spike significantly. While you might find similar low prices until 20 days before departure, waiting until that point increases volatility and risks higher costs, where prices can climb from $373 to $564. For peace of mind, consider booking between 126 and 114 days prior for nearly the same rates and better seat selection.