Udon Thani is one of the best places in Thailand to eat Isan cooking — the spicy, fermented, grilled cuisine of the Lao-influenced northeast. The unmissable dishes are som tam (papaya salad), gai yang (grilled marinated chicken), larb (chopped meat salad with herbs), nam tok (a similar salad of grilled beef), and sai krok Isan (the local fermented pork sausage).
Eat at the night-time stalls around Nong Prachak Lake, in the central market, and along Pho Si Road in the evenings. For sit-down meals, VT Namnueng is a famous local Vietnamese restaurant chain that originated in Udon — the do-it-yourself spring rolls of grilled pork sausage and herbs are the signature dish. Rabieng Patchanee is the reliable go-to for upmarket Thai cooking with a quieter setting.