See chapter 1 of publication 463.
https://www.irs.gov/publications/p463#en_US_2022_publink100033749
If the travel was primarily for business, there are special rules to follow when the travel is outside the US. Primarily for business might mean that you were required to work on site for a client or meet with the client in person over several days. If you add a personal vacation to a trip that is primarily for business, some of your business expenses are allowable.
However, if the purpose of the trip was primarily personal, you can't deduct meals, lodging or travel expenses as a business expense. The only expenses you could deduct would be expenses that you only incurred because of the business and would not have incurred if not for the business activity.
