eSIM4

eSIM4 partners with KT, one of South Korea's three major carriers, to deliver fast mobile data for Seoul and nationwide coverage. Their plans start at $2.98 for short stays and scale up to unlimited data options, making them competitive for budget-conscious travelers. Activation is instant once you purchase a plan online.

This service works well if you want reliable coverage at bargain-basement prices without the brand prestige of the official carriers. You'll get genuine 4G/LTE speeds across Korea's modern network, though data speeds depend on which premium plan you select.