Reviewing Rare Forms of ID Documents Worldwide

Diplomatic passports differ from standard passports in that they don’t act as proof of citizenship, but rather an individual’s official status as a state representative. The moment that status ends—whether due to resignation, dismissal, or completion of a diplomatic mission—the document becomes invalid. 

The history of diplomatic travel documents goes back to ancient times, with Mesopotamian envoys carrying tablets or scrolls that acted as letters of credence. However, more modern standards were shaped at The Vienna Convention on Diplomatic Relations in 1961. It formally recognized diplomatic passports as an essential instrument for international relations, and standardized the framework for diplomatic immunity and travel.

Many often assume a diplomatic passport grants its owner immunity and easier border crossings. In reality, these privileges are not absolute—diplomatic immunity does not provide blanket protection from legal consequences, and some countries impose restrictions on what diplomats can do on their soil.

As for security features, most nations today issue biometric diplomatic e-passports with RFID chips, fingerprint recognition, holographic overlays, UV-reactive ink, and many other features. For more specifics, let’s look into the following example:

Germany unveiled the latest version of their diplomatic passport in 2024 with a number of security updates, but leaving the external look mostly unchanged compared to the 2017 version. The booklet follows the standard EU passport size of about 88×125 mm (ICAO ID-3 format); however, it contains more pages (48) than ordinary German passports (32, although 48-page versions are available for frequent travelers​).

The passport embeds a contactless RFID chip storing the holder’s personal data, digital photo, and two fingerprints​. The data page is made of polycarbonate, with holder information and the photograph laser-engraved. A tactile intaglio printing is used on certain text (such as the passport number or expiration date), providing a raised feel that can be verified by touch. It also features a standard machine-readable zone (MRZ), UV fluorescent ink, embedded microtexts, and holographic elements that change appearance when viewed at different angles.

All personal data fields and the issuing authority are printed in German and English, and the passport contains a note in German, English, and French explaining that it is a diplomatic passport requesting foreign authorities to grant privileges and assistance to the bearer (a standard diplomatic courtesy note). The holder’s personal data itself is recorded using Latin script with German diacritics as needed, per ICAO standards.

A German diplomatic passport’s validity is determined by the length of the holder’s official assignment or term of office​. When a diplomatic passport expires or the holder’s role ends, the passport must be returned to the Foreign Office (since it remains government property)​.

Holders of the passport often benefit from certain practical privileges. For example, they can clear customs/immigration through special diplomatic channels in many airports. Many countries also exempt visas for German diplomatic or official passport holders as a gesture of goodwill and reciprocity​. However, these privileges are based on international agreements; the passport itself contains a note requesting such courtesies.

Emergency travel documents are a temporary solution for cases when a traveler loses their passport abroad. They are usually issued under strict conditions and often with severe limitations—some only allow a single journey, while others restrict travel to specific countries. 

And, despite their stopgap nature, emergency passports are not easy to produce, nor are they devoid of security features. For example, here’s what we can find in Belgium’s current version of the document:

Belgium’s emergency passport, officially termed a provisional passport, is issued as a passport booklet (dark green cover) with limited pages (only 6 pages in the emergency travel document issued abroad)​.

It is only intended for extreme cases and comes with a warning that it may not be accepted universally. The Foreign Ministry explicitly notes it “does not allow travel in all countries in the same way as the standard passport”.​ Just like an emergency US passport is not valid for visa-free entry into Belgium​, Belgian provisional passports might not be accepted under visa waiver programs.

Like regular Belgian passports, it features secure printing and includes basic security elements such as guilloche background patterns, microprinted text, and OVI. It is also machine-readable with an ICAO-standard MRZ.

However, being an emergency issue, it does not contain the full suite of security features found in ordinary passports​. Most notably, emergency travel documents omit RFID chips and holographic overlays.

Statelessness is not as uncommon as one might think. Territorial disputes, gaps in nationality laws, the dissolution of states, or targeted policies that strip certain populations of citizenship are still affecting millions of people worldwide.

And without citizenship, they are quite limited in their means to cross international borders. Stateless persons and foreign residents who cannot obtain passports from their country of residence rely on specialized travel documents that come with restrictions of their own, on top of higher scrutiny at border crossings.

The 1954 Convention Relating to the Status of Stateless Persons established a framework for issuing travel documents to such individuals, but their level of acceptance depends on diplomatic relationships and national security policies. These do not confer nationality, but rather provide a means for the holder to leave and re-enter the country where they reside.

Poland’s Polski dokument podróży dla cudzoziemca (Polish Travel Document for Foreigners) is issued as a passport-style booklet. It historically has a different, blue cover color and embossing than red Polish national passports to distinguish it​. 

The dataset is rather standard, however: sometimes holders of this document often have “XXX” or “stateless” entered as nationality if they truly have none. If they do have a nationality (like a citizen of country X who can’t get a passport), the document might still list that nationality, or just list the place of birth and leave the nationality blank.

The 2022 version includes numerous modern security features:

• A bespoke multi-tonal watermark in the paper that is visible in different shades when held to light​.

• A laser-perforated serial number through all pages, which is the document’s number—glowing under light and impossible to alter without damaging the booklet​.

• OVI is used in the country name or coat of arms on the cover—it changes color when viewed at different angles.

• Holographic overlay (Poland’s eagle emblem) that overlaps the photo area.

• Under UV light, the travel document reveals hidden patterns (fluorescent inks showing the Polish emblem or ornamental designs). 

• Under IR light, certain printing appears or disappears.

The 2022 redesign also introduced an embedded microprocessor chip in the polycarbonate page (the document has an electronic module integrated)​. This chip stores the holder’s facial image and fingerprints, in line with EU Regulation 2252/2004, which Poland applies to travel documents as well​. And, of course, the document has an OCR-readable MRZ on the data page, so even if the chip isn’t read, the data can be scanned and run through databases.

The Polish travel document for foreigners is valid for 1 year from the date of issue​. After one year, if the person still needs it (and still cannot get their national passport), they must apply for a new one.

Given their unique role, seafarers require special forms of ID that not only verify their identity but also grant them access to various ports across the globe. This role has been taken by Seafarer Identification Documents (SIDs), the most recent version of which was adopted at the Seafarers' Identity Documents Convention (Revised) in 2003.

Historically, seafarer IDs were rather simple booklets with basic personal information; however, post-9/11, there was a demand for enhancing the security of these documents. Most notably, the 2003 convention mandated the inclusion of biometric data in SIDs. 

Let’s now take a look at Azerbaijan’s example:

Azerbaijan’s SID is an ID-1 sized card, with the front displaying the bearer's standard personal details: name, date of birth, nationality, physical description, and a unique document number. There is also typically a digitally printed signature of the bearer. The back includes the issuing authority (State Maritime Administration), as well as the MRZ and a 2D barcode containing the seafarer’s fingerprint data in numeric form. 

Unlike e-passports, seafarer identification documents do not necessarily have an RFID chip. The standard approach is the printed 2D barcode and MRZ rather than a contactless chip, mainly to keep it simple (not all ports have e-chip readers, but barcode scanners are common)​. But even so, not all port officials are well-trained in reading the SID’s barcode. Some might still rely on older seamen’s books (which often just had a photo and basic info); in those cases, they might just treat it as an ID and call the ship’s agent to confirm the person is a crew member.

Once issued, the seafarer’s ID is not a full passport but a specialized travel document. It is used when the seafarer goes ashore in foreign ports (for shore leave) or when joining or leaving ships through countries in transit. Typically, a seafarer will carry both their national passport and their SID. The SID allows them to disembark at ports without needing a visa for short stays, but only if the country recognizes Convention 185, of which there are only 39. 

Convention 185 doesn’t strictly define validity, but SIDs are often valid for about 5 years (some countries choose 5 or up to 10). This is a healthy enough balance, as seafarers don’t want to renew too often, but also not have an ID out for too long if the tech is updated.

UNLPs are issued to United Nations officials and certain employees of related international organizations. This includes staff of the UN Secretariat, specialized agencies (like WHO, IMF, World Bank, IAEA, etc.), and certain other organizations that have an agreement with the UN​. Recognized under the 1946 Convention on the Privileges and Immunities of the United Nations, the UNLP is acknowledged by member states as a valid travel document.

A UNLP is a passport-style booklet that comes in two colors: blue covers for most UN officials/staff and red covers for high-ranking officials (D-2 level and above, akin to diplomatic status)​.

The personal data page of modern UNLPs is polycarbonate for biometric versions (since 2010). It has a visual zone with the holder’s photo, personal details (name, date of birth, etc.), document number, and text indicating it was issued by the United Nations​. It also indicates the bearer’s position or organization (e.g., “United Nations—Staff” or a specific agency like “ILO”). The data page is machine-readable with an MRZ, and has an embedded RFID chip with the holder’s personal data​. A laser-engraved ghost image of the photo, microtext printing and holograms are also present as anti-counterfeit measures.

A UNLP does not guarantee visa-free entry. Holders still often need to get visas for official travel, although they might get special “diplomatic visas.” Some countries (like the US) do not consider a UNLP sufficient for entry—the traveler must have the appropriate visa in their national passport, and the UNLP is just shown for courtesy. That is why UNLP holders usually travel with two passports—their Laissez-Passer and their national passport.

Older UNLPs could list spouses and children, meaning the family traveled on one document, but this has since been phased out​—now, everyone gets their own document.

With so many not-so-common ID documents in circulation, officials need an automated ID verification solution that will work with every type of document—and not only that.

The solution should also be able to:

• Automatically detect document type. 

• Read machine-readable zones (MRZ) and barcodes.

• Recognize and validate various security features, including holograms and optically variable ink (OVI).

• Verify RFID chips and authenticate biometric data.

• And more.

Regula Document Reader SDK is equipped to handle all these challenges, enabling easy verification of even the rarest identity documents. 

Have any questions? Don’t hesitate to contact us and we will tell you more about what our solutions have to offer.