esimNB

esimNB is built for budget-conscious travelers who want to avoid overpaying for data in Korea. Their entry-level plans start at just $2.00 for 1GB over 30 days, with top-up options if you run through your allowance early. The service runs on SK Telecom and LG U+ networks, which provide solid coverage across the country including smaller towns outside Seoul.

Pick esimNB if you're a light data user who mainly needs maps, messaging apps, and occasional browsing. The pricing is genuinely the cheapest on this list for minimal usage, though data speeds won't match the premium carriers' 5G rollouts. Activation happens through their website, and you'll receive your eSIM code via email instantly.