Can I transfer Capital One miles to United MileagePlus? No, you can't transfer Capital One miles to United, but you can transfer your miles to Air Canada, Avianca, Turkish, or Singapore to book United flights. These four airlines are Star Alliance members and can book flights on United.

Capital One does not have a direct 1:1 transfer partnership with United Airlines, meaning you cannot move Venture or Spark miles directly into a United MileagePlus account. However, you can still use Capital One miles for United flights through several indirect methods. First, you can book United flights via the Capital One Travel portal using your miles at a rate of 1 cent per mile. Second, you can use the "Purchase Rate" feature to offset the cost of a United ticket bought directly with your card within 90 days. Third, and most strategically, you can transfer Capital One miles to Star Alliance partners that do have transfer agreements, such as Air Canada Aeroplan, Avianca LifeMiles, or Turkish Airlines Miles&Smiles. You can then use those partner miles to book "Award Space" on United-operated flights. While this requires checking for availability on the partner website, it often provides better value than a direct portal booking.