Checking a bag across two reservations
 

I have two different reservation on the same day with the first trip ending where the second start. Is it possible to check a bag all the way through and not having to do it again in the middle?

Too little information.
Easy answer... if it is all Delta, probably.
Otherwise.. please share more info.

Checking a bag across two reservations
 

Assuming both itineraries are on Delta metal - yes. You may need to mention it when you check in.

See attached -- this has the information. For most partners they will check it even if it is on 2 tickets:

https://pro.delta.com/content/deltap...e-policy-.html

Yet another example where DL is helpful while AA tells you to pound sand. My mother had an AA ticket from MIA-MAD and then a separate ticket from MAD onwards with Iberia (you know - one of the oneworld partners), AA refused to check bag through

The OP still needs to be concerned with timing. If the two-ticket transfer doesn't meet minimum connect time the DL checkin agent is likely to reject it. If the transfer exceeds max bag hold time an agent is likely to reject it. That varies with domestic and international itineraries.

The one time I tried this I was successful. Just ask the TA politely when you drop off the bag.

OP - As you can see, you are receiving random bits of information here including what happened to various peoples' relatives on one-off's at outstations.

In order to get an accurate answer, please provide your exact routing, the carrier(s), flight numbers and timings.

not true - I posted a link to an official delta policy. Provided he meets those requirements he should have no problem. (probably helpful to print out the policy with you in case you get an agent that doesn't know)

Not necessarily. I just returned from a three segment itinerary, MCO-DFW-MEX-SCL and return, on AA-AA-AM** respectively. Everything was ticketed by AA but MCO/DFW was ticketed separately. AA in MCO checked our bags all the way through to SCL*. On the return, AM checked them to DFW only and we had to get new tags for the last segment.

*one got lost for 12 days but that's beside the point.
**AM is SkyTeam, not OneWorld

You just got an agent that didn't know what they were doing. AA's policy is that they will check through on separate tickets as long as all carriers are within oneworld, which is actually less restrictive than Delta's as per Delta's policy they will only check through to certain SkyTeam partners, not all.

I love it when people bring printed policies, especially for int'l travel. Domestic policies are easy to find, but this speeds up the checkin process if you have the time to print it out. Any policy can be found, but it's just faster to have a complete sentence to search for to narrow results. OP should print out that pro.delta.com page in case

"To help check me in as quickly as possible, I printed this out to help you find what you need" :D