Sonic Drive-In is adding a tangy twist to the lineup of iconic St. Patrick's Day beverages. While green beer and McDonald’s Shamrock Shakes have long been fixtures of the holiday, Sonic is aiming to captivate sour flavor lovers with its own addition: the Sour Shamrock Slush.

This daring new beverage draws upon the tartness of green apple for its distinct flavor. Echoing the visual appeal and taste of an Appletini, the slush is expected to be a refreshing departure from the typically minty holiday refreshments. Its bold green color is courtesy of a sour green apple syrup, and the experience is amplified with the addition of sour popping candy running through the drink.

A verbal snapshot from Sonic’s press release describes the Sour Shamrock Slush as a “treat for the eyes and a jolt of fun for the taste buds”. Topped with a dollop of whipped cream and extra popping candy, and garnished with a rainbow sour candy strip, it promises a "puckering kick" in every sip.

Now available for purchase nationwide, Sonic's seasonal offering will continue through March. It can be purchased in a 20-ounce size for $3.99.

An increasing consumer interest in sour flavors over the past year has made a mark on the confectionary world. Outlets such as TODAY.com have highlighted this trend, citing a 309% sale growth in the sour category for restaurant supplier Baldor Specialty Foods between 2022 and September 2025.

Sonic confirmed that this growing desire for tangy flavors was the inspiration behind the Sour Shamrock Slush, noting to Food & Wine, "Flavor trends are all about surprise and satisfaction, and the Sour Shamrock Slush delivers on both. It pairs the sweet‑sour flavor combo fans want with frozen refreshment, creating a craveable, Instagram-worthy experience our guests come to Sonic for."

The question remains whether the Sour Shamrock Slush will be the next big St. Patrick's Day beverage hit. Can Sonic’s tangy concoction garner a following that challenges the popularity of McDonald’s iconic minty Shamrock Shake? Only time will tell.