**Admission to Bosnia is possible; boarding the flight needs a separate arrangement with the airline.** Having the ID in Sarajevo could help establish citizenship, but simply leaving it with airport officials does not guarantee boarding.

Bosnia’s embassy in Canberra publishes guidance confirmed by Bosnian Border Police: dual citizens may enter using a Bosnian ID card, and even without the prescribed travel documents, entry is allowed once officials establish Bosnian identity and citizenship. Additional checks—and potentially proceedings over missing documents—may follow. This supports admission in your situation, but does not specifically confirm a procedure for a relative delivering the ID at the airport. [Embassy guidance](https://www.bihembassy.org/index.php?Itemid=117&id=305:ulazak-u-bosnu-i-hercegovinu-drzavljana-bih-koji-imaju-dvojno-drzavljanstvo-vazna-informacija&lang=bs&option=com_k2&view=item)

The Croatian passport alone does not meet the published entry requirement for Croatian visitors: it must remain valid for at least three months after departure from Bosnia. [Croatian Foreign Ministry](https://mvep.gov.hr/konzularne-informacije/vize-22733/pregled-viznog-sustava/22853?country=17)

With only hours remaining, I would pursue these steps immediately:

1. **Have the relative call Sarajevo Airport Border Police:** **+387 33 755 359**, email **sarajevo@granpol.gov.ba**. Explain the dual citizenship, available Croatian passport, and original Bosnian ID held locally. Ask whether officials can inspect the ID, arrange its presentation on arrival, and confirm acceptance directly to the airline. [Official contact details](https://granpol.gov.ba/hr/postrojbe-granicne-policije6)
2. **Go to Lufthansa’s airport check-in supervisor in Lisbon**, carrying the Croatian passport, photographs of both sides of the Bosnian ID, flight details, and the embassy guidance. Ask the supervisor to obtain direct confirmation from Sarajevo Border Police and approve carriage through to Sarajevo.
3. **Include the airline operating the Sarajevo leg**, if different from Lufthansa. Approval needs to cover that flight as well.

Officials might be willing to communicate acceptance, but **I found no published procedure guaranteeing such clearance or requiring Lufthansa to accept it**. Lufthansa’s conditions permit refusal when travel documents are incomplete, so a relative’s assurance or an ID photograph alone is insufficient to rely on. [Lufthansa conditions, Article 13](https://www.lufthansa.com/content/dam/lh/documents/terms-conditions/2026_02_ABB_en.pdf)

Assuming the connection is in Germany, the Croatian passport’s short remaining validity is not itself a Schengen problem: EU citizens need a passport or national ID valid on the travel date. The obstacle is documenting acceptance for Bosnia. [EU guidance](https://europa.eu/youreurope/citizens/travel/entry-exit/eu-citizen/indexamp_en.htm)