Not all IDs are created equal—some are only meant to verify a person’s identity, while others also act as proof of their qualifications. Documents for seafarers, pilots, police officers, and even dentists are in circulation around the world. They’re not as common as national IDs or passports, but they still need to be verified.
These rare documents can be hard to authenticate, because there may not be established processes or practices in place.
In this article, we’re going to explore the topic of rare ID documents and describe what makes them stand out.
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Seafarer’s Identity Document
Seafarers require special forms of ID that verify their identity and grant them access to various ports across the globe. Seafarer Identification Documents (SIDs) play this role, with the most recent version adopted at the Seafarers' Identity Documents Convention (Revised) in 2003.
A “seafarer” in this context means any person who is employed or works in any capacity on a ship (other than a warship). This includes crew like officers, engineers, and deckhands, as well as staff like cooks—essentially anyone with a seafarer’s labor card.
Historically, seafarer IDs were simple booklets with basic personal information; however, post-9/11, there was a demand to enhance the security of these documents. Most notably, the 2003 convention mandated the inclusion of biometric data in SIDs.
Spain’s Seafarer’s Identity Document
Spain ratified Convention 185 in 2011, and introduced a compliant seaman’s book a year later, in 2012. Pre-2012, Spanish maritime professionals relied on a simpler seafarer ID known as the Libreta Marítima, a compact booklet primarily issued for recording sea service details rather than a robust travel document.
The 2012 seafarer ID was a passport-sized booklet, featuring the Spanish coat of arms on the cover.
Inside, the booklet contained pages for recording sea service, as well as a personal data page with a machine-readable zone (MRZ) and a digital photograph of the holder.
The document featured a 2D barcode containing the holder’s fingerprints, as well as microprinted text, holographic elements, watermarks, and UV fluorescent ink.
In 2022, Spain began phasing out the booklet-style SID in favor of a more modern ID-1 card format. Both formats are expected to coexist until the last issued booklet-style seafarer ID expires.
The latest Documento de Identidad de la Gente de Mar (DIM) is more intricate in its design and security elements:
The bearer’s photograph is laser-engraved in the polycarbonate card, with a secondary “ghost” image printed to the right.
The card’s background is composed of fine guilloche waves representing the sea, interwoven with microtext and the red-yellow colors of the Spanish flag in subtle curved lines.
A repetitive “España” pattern in microprint is used both as decoration and a security feature.
Both the front and back of the DIM incorporate a special circular emblem—a seal-like graphic visible under normal light. It allegorically depicts mariners from three ship departments (deck, engine, and radio).
UV printing on the DIM reveals additional motifs: under UV light, one can see luminescent compass roses and the fluorescent text “DIM”.
The card also contains an RFID chip that stores the facial image (replacing the fingerprint), similar to an eID or e-passport.
Estonia’s Seafarer’s Discharge Book
Unlike Spain of late, Estonia issues a SID in the form of a Seafarer’s Discharge Book, most recently updated in 2021. The book consists of a navy-blue cover and 64 inner pages for records, and it serves as both an identity booklet and a log of a mariner’s service.
The cover is made of flexible plastic with a hot-stamped gold coat of arms.
The inside front cover is printed in intaglio with fine-line engravings. This includes a latent image that displays the text “EESTI ESTONIA” when the page is viewed at an angle.
The data page is printed with a multi-color guilloche background, incorporating rainbow printing (an iris blend of hues from grey to blue and back to grey) across the page.
The data page inside contains the holder’s photograph and standard identifying information. It is protected by several security features such as UV fluorescent ink, holograms, watermarks, a transparent window, and an RFID chip. The booklet also includes an MRZ on its data page and is valid for up to 5 years for Estonian citizen seafarers.
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 40.
Crew Member Certificate
Not to be confused with airline-issued crew IDs, a crew member certificate (CMC) is an official document issued by the state. It serves as a visa waiver credential for aircrew, allowing verified crew members to clear immigration in many countries without a traditional visa.
CMCs have seen limited use historically, as many countries simply relied on crew passports and visas. However, efforts have been recently made to standardize and modernize these credentials. The latest CMCs are produced as ICAO-compliant machine-readable cards, typically in the ID-1 size. According to ICAO guidelines, the card must have at least the holder’s name, DOB, nationality, crew ID number, issuing state, and validity period printed on it, plus a description of the holder (usually their rank or crew position).
South Africa’s Crew Member Certificate
South Africa’s CMC was introduced in late 2010 and was officially issued in 2011. It is widely considered a state-of-the-art smart credential and the best of its kind in Africa, with multiple security layers similar to those found in national e-ID cards and e-passports.
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The holder’s photograph is laser-engraved in black-and-white on the card surface. Along with the photo, all personal data (name, nationality, date of birth, crew ID number, etc.) and the issuing authority info are also laser-personalized.
The South African CMC is an electronic ID, as it incorporates a contactless RFID chip with biometric data. On top of that, it features a Changeable/Multiple Laser Image (CLI/MLI) in the bottom right corner (“ZAF RSA 28208” in the specimen), as well as optically variable ink that changes color from brown to green under different viewing angles.
The CMC contains invisible UV fluorescent printing: under ultraviolet light, one can see several wavy lines, globes, and altered versions of the South African flag.
It also has a holographic element with a dynamic multicolor effect under various lighting (the national flower or the text “RSA” might appear and shift).
The document carries a ten-year maximum validity, tied to the individual’s continued crew status—if a crew member leaves the airline, the certificate is canceled.
Finland’s Crew Member Certificate
The Finnish Transport and Communications Agency (Traficom) produces a CMC for crew of Finnish-registered airlines which is valid for 5 years. Finnish authorities only issue the card after thorough background checks (similar to airport security badge vetting) so that only trusted crew can obtain one.
It is a polycarbonate card that contains the crew member’s photo, personal details, and the specific airline’s identification.
As for security features, Finland’s CMC includes a multiple laser image (MLI) of the holder’s portrait, three dotted lines printed in UV ink across its front, and a hologram. Additionally, it carries an MRZ on the back.
When scanned, Finnish CMCs are recognized by immigration systems and treated as official IDs, eliminating the visa requirement in many cases. However, crew must still carry their passports.
Armed Forces ID Card
Unsurprisingly, members of military or defense forces in most countries also hold a special kind of ID document—an Armed Forces ID Card. It usually confirms the holder’s identity, as well as their status as active duty, reserve personnel, retired military, or a dependent family member.
USA’s Common Access Card and Uniformed Services ID
A prime example is the U.S. Department of Defense Common Access Card (CAC) and the related Uniformed Services ID cards. Earlier generations (through the 1990s) were laminated cardstock documents with a photo, name, rank, ID number, and an embossed seal. They were functional, but not the most secure.
A Common Access Card (left) and a Uniformed Services ID card (right).
The latest major upgrade to the CAC dates back to 2006, when it was standardized in line with the Homeland Security Presidential Directive 12. New CACs boast integrated circuit chips capable of storing digital certificates and biometric data. Another notable upgrade happened in 2018, when the magnetic stripe was removed, as it was becoming obsolete.
The polycarbonate card’s background contains microprinted text—it has “U.S. DEPARTMENT OF DEFENSE” repeated in fine print across the front as a background pattern. When tilted, one can often spot an optically variable device (OVD) embedded in the laminate (the U.S. cards have a holographic eagle). Under UV light, the CAC shows fluorescent patterns and the letters “USA”, which are invisible in normal light.
The new “Next Generation” USID cards for retirees and dependents, though lacking chips, share the same advanced printing and materials.
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Older USID cards (left) were color-coded by category (blue, green, red, etc. for different personnel types) and will be phased out by 2026, replaced by the uniform white smart card on the right.
Some European armed forces’ IDs similarly have moved to polycarbonate smart cards, often compliant with the NATO STANAG for identity documents, meaning they can include features like an X.509 certificate for coalition network access.
Professional ID Card
Without being tied to a specific occupation, professional ID cards act as proof of qualification for a number of high-responsibility jobs (e.g., doctors, nurses, lawyers, teachers, engineers, accountants, architects, and others).
The Philippines’ Professional ID Card
The concept of a professional identification card (PIC) in the Philippines dates back to the 1970s. The Professional Regulation Commission (PRC) issued paper-based registration cards as far back as 1977. Those early IDs were basically paper certificates or small booklets. By the 1990s, the PRC moved to credit-card-sized IDs with lamination. However, until recently, the security was minimal: older PICs were essentially printed on plain card stock with the bearer’s info, laminated with a plastic film, and they relied on the PRC dry seal (embossed stamp) and a printed signature of the PRC Chair for authenticity.
In 2012, the PRC introduced a more standardized PVC card (with a uniform design for all professions) and bolstered it with a number of security elements like microprinted text, UV fluorescent ink, and a ghost image of the holder.
The 2019 upgrade saw some design changes, both subtle and not-so-subtle. For example, the professional’s photo was relocated, and the ghost image was removed.
Overall, the purpose of the redesign was to make PICs look more simple, in line with modern trends; that’s why the wavy lines and the faint PRC logo at the center were changed to a plain white background. On the back, the same pattern can be observed: the new ID lacks information such as the main office address and the hotline number.
The upgraded 2019 version shares all the same security elements as the 2012 version, including the professional’s signature digitally printed on the back.
It’s also worth noting that since February 27th, 2023, professionals also have an electronic copy of their PICs, which they can print out and use as the equivalent of the real physical document. However, in this case, the printed document should be subject to verification via the PRC website or an IDV solution like Regula Document Reader SDK. The key difference between the two is that Regula Document Reader SDK is an out-of-the-box solution that can verify over 15,000 document templates worldwide, while the PRC website is only meant for PIC checks.
How to effectively process professional IDs
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 the document type.
Read machine-readable zones (MRZ) and barcodes.
Perform document liveness checks and analyze dynamic security features.
Recognize and validate holograms, MLI, 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, making it easy to verify 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.
