A lap infant on a Delta SkyMiles award is free on domestic flights and costs 10% of the adult cash fare internationally. You can usually add the infant online through My Trips, though several parents booking award tickets specifically have needed to finish the process by phone. Book and ticket the adult award first, then add the infant.

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That's the outline. Where it gets more involved is when a SkyTeam partner is operating the flight, or when you're trying to sort this out at the airport instead of ahead of time.

What does a lap infant cost on a Delta SkyMiles award?

Delta's structure follows the common pattern: free on domestic itineraries, 10% of the adult cash fare on international ones. That percentage applies to the current cash price of the cabin you're flying, not to the number of miles you redeemed for the adult ticket.

On a Delta One redemption, that 10% can add up to a real number, not a token fee. Get an exact quote for your specific route and cabin rather than assuming it'll be minor.

Can you add the infant online, or do you need to call?

For most itineraries, you can start the process online through My Trips. Several parents booking award tickets specifically, rather than revenue tickets, have reported the online tool struggling to complete the addition, which means a follow-up call to Delta is sometimes needed to finish the job. Budget time for both, particularly on international award bookings.

Should the adult award be ticketed first?

Yes. Book and fully ticket the adult SkyMiles award before adding the lap infant. This is standard across nearly every program in this comparison, and Delta is no exception.

Does the infant need their own SkyMiles account?

Not for a lap infant. If you're booking a full seat for a child two or older, giving them their own SkyMiles number lets that child start earning miles on the ticket, but it isn't required simply to add a lap infant to your reservation.

Who adds the infant on a SkyTeam partner award?

This is the part of Delta's process that needs the most attention. When Delta operates the flight, the infant addition is a Delta-handled process end to end. When a SkyTeam partner, like Air France, KLM, or Virgin Atlantic, is operating any part of the itinerary, the process can require a phone call and longer processing than an all-Delta itinerary.

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If you're using SkyMiles for a partner-operated flight and a lap infant is part of your plan, confirm directly with Delta whether Delta or the operating partner is responsible for adding the infant, and don't assume the process will move as quickly as it would on Delta's own metal.

What happens if the infant turns two mid-trip?

The relevant age is your child's age on each individual flight date, not the date you booked. If your child turns two between your outbound and return flights, the return leg needs a full child ticket instead of a lap infant fare.

Common booking failures parents run into

The most frequently reported issue is agents needing meaningfully longer to process an award-ticket infant addition compared to a revenue-ticket one, sometimes well beyond what a parent expects from a routine call. This is exactly why departure day is the wrong time to try to sort this out for the first time.

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The second common issue is assuming the online My Trips tool will complete the whole process for an award booking. It often starts the process, but a phone call is needed to finish it, particularly for international itineraries.

A worked example

A parent flying Delta One from Atlanta to Amsterdam adds a lap infant by phone after the adult award has ticketed. The agent quotes roughly 10% of the current Delta One cash fare for that route, plus the standard taxes that apply to lap infants on the itinerary. Because the flight is Delta-operated the entire way, there's no partner complexity, but the call still takes longer than the parent expected, given how the award-ticket infant process compares to a revenue booking.

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Compare that to a parent using SkyMiles for a Virgin Atlantic-operated flight as part of a SkyTeam-adjacent partnership. The infant addition requires confirming with Delta which airline is actually responsible for processing it, adding an extra step that wouldn't exist on an all-Delta itinerary.

When to call Delta vs. handle it yourself

For a domestic lap infant, the online tool is usually sufficient, and a call isn't typically necessary.

For any international Delta-operated flight, start online, but expect to finish by phone, and don't leave this until the day of travel.

For any SkyTeam partner-operated award, confirm with Delta ahead of time whether they or the partner airline handles the addition, since this is where processing time and responsibility get genuinely unclear.