In certain circumstances, the IRS dictates that travel insurance for self-employed persons is tax-deductible. 

The deductible travel expenses, for a business trip, would include the cost of travel insurance, visa fees, customs fees, and books about the destination (TC Memo 1998-272), and would be deductible on Schedule C as a travel expense for a self-employed individual or, in years other than 2018 through 2025, as a Schedule A, miscellaneous itemized deduction for an employee.

Although there are no specific citations to reference, it would seem that the medical portion of the travel insurance premium–if it is separately stated–for a self-employed individual and more-than-2% S corporation stockholders (corporate wages count as SE income for purposes of the net income limitation) would qualify for the above-the-line SE medical deduction (see next topic) whether or not the trip was for business (Sec 162(I)(1)(B)).

It would also seem, where the above-the-line SE medical deduction does not apply, the medical portion of the travel insurance would qualify as a Schedule A medical deduction–again, only if the medical portion of the premium is listed separately from other coverage such as for trip delays, lost or damaged luggage, or trip cancelation.