The Brexit negotiators agreed to have a transition period starting from the beginning of the UK's withdrawal from the Union to the end of 2020. One important implication that this agreement holds for the EU's existing FTA partners, including Korea, concerns the application of the existing agreement to the UK during the period. The Brexit negotiators have agreed that the Union's existing FTAs will be applied to the UK during this period. It is unclear, however, whether this will be accepted by the other parties to these FTAs who have no legal obligation to do so, according to experts. The UK accounts for more than 1%, or more than 10 billion USD per year, of Korea's exports, and is the country's third-largest non-Asian trade partner. The Korea-UK trade volume is in a rising trend since the Korea-EU FTA went into effect. Import from the UK also allowed Korea to diversify its crude oil sources, reducing the country's exposure to the volatility in major oil-exporting regions. Given the importance of Korea's trade relations with the UK, the Korean government must promptly determine its stance on this issue. Although the decision whether to continue applying the existing FTAs to the UK during the transition period is up to the partner countries, the EU and the UK can engage more actively in its making than merely notifying their agreement to the partners as planned in the draft agreement.