Vision, hearing and physical-ability standards checked against 46 CFR Part 10, Subpart C · September 2026
Why this comes first
People spend thousands on courses, sea-time plans and travel before they find out whether they can pass the Coast Guard medical. Find out first. The good news is that the answer is rarely a simple yes or no. The Coast Guard can approve you, ask for more information, issue a medical certificate with a waiver or operational limitations, or deny it. What's required also depends on the endorsement and duties you're after.
These are civilian merchant-mariner standards. They're separate from military enlistment standards, so a condition that kept someone out of the service doesn't necessarily keep them off a ship.
Eyesight and color vision
You don't need 20/20 vision, and glasses or contacts don't disqualify you. The standards are specific, and they differ by department 46 CFR 10.305.
| Situation | What to know |
|---|---|
| Deck (national endorsements) | Correctable to at least 20/40 in one eye, with uncorrected vision of at least 20/200 in that same eye. |
| Deck with STCW | New applicants must meet those same numbers in both eyes. Mariners who held an MMC before January 1, 2017 may continue under the one-eye standard. |
| Engineering and certain other endorsements | Correctable to at least 20/50 in one eye, with uncorrected vision of at least 20/200 in that same eye. |
| Very poor vision without glasses | A waiver may be possible when your corrected vision meets the standard. Expect to be required to carry corrective lenses, and possibly a spare pair, aboard. |
| Color vision | Deck applicants must pass a Coast Guard-accepted color-vision test. Engineering and certain other endorsements only need to distinguish red, green, blue and yellow. Color-correcting lenses can't be used to pass. If you fail one screening test, ask which other accepted tests apply before assuming the door is closed. |
| Loss of sight in one eye | Reviewed individually. You must wait six months from the loss before applying and provide a statement of demonstrated ability. |
Hearing
When specialist testing is needed, the audiometer standard is an average unaided threshold of 30 decibels or less in at least one ear at 500, 1,000, 2,000 and 3,000 Hz. The functional speech-discrimination standard, tested at 65 decibels, is 90% for an original credential or endorsement and 80% for a renewal or raise of grade 46 CFR 10.306.
Hearing aids can be acceptable through a waiver. If you need them, you'll have to wear them on watch and carry spare batteries.
Physical ability: can you do the job safely?
The question isn't whether you have two arms and two legs. It's whether you can safely do the shipboard work. An amputation, prosthesis, joint replacement or other disability gets an individual assessment, and this page can't tell you how yours will come out.
Where a physical-ability demonstration is required, which covers officers, AB and QMED ratings, lifeboatmen, and most ratings on STCW vessels, the examiner checks whether you can 46 CFR 10.304:
Walking comfortably around a clinic doesn't prove all of that. If any item worries you, practice it and raise it with the examiner up front.
Conditions to talk over with your examiner
None of these is an automatic disqualification. The Coast Guard's concern is whether a condition, or its treatment, creates a significant risk of sudden incapacitation or gets in the way of doing the job safely. A diagnosis alone isn't an eligibility decision.
| Area | Raise these early |
|---|---|
| Blood pressure | High readings, poor control, dizziness, medication side effects. Taking blood-pressure medicine doesn't by itself make you unfit. |
| Diabetes | Type 1 or Type 2, insulin or other medicines, blood-sugar control, severe low-sugar episodes, and complications affecting eyes, feeling or kidneys. |
| Heart and circulation | Heart attack, chest pain, heart failure, rhythm problems, pacemaker or implanted defibrillator, blood clots. |
| Mental health | Depression, anxiety, PTSD, bipolar disorder, psychiatric hospitalization, any history of self-harm. Current stability, treatment, day-to-day functioning and medication effects are what matter. |
| Sleep and alertness | Sleep apnea and CPAP use, narcolepsy, excessive daytime sleepiness. |
| Neurological | Seizures, unexplained blackouts, stroke, significant head injury, tremor, poor coordination. |
| Breathing and lungs | Asthma, COPD, shortness of breath, oxygen use. |
| Bones, joints and strength | Severe arthritis, back problems, limited movement, amputation or prosthesis, incomplete recovery from surgery. |
| Balance and inner ear | Vertigo, recurring dizziness, falls. |
| Kidneys and digestion | Kidney disease, recurrent stones, dialysis, serious liver disease, inflammatory bowel disease, recurrent bleeding. |
| Other significant conditions | Cancer and its treatment, organ transplant, severe allergies, blood disorders, infectious conditions. |
| Medications and substance use | Prescription and over-the-counter drugs that cause drowsiness or affect judgment; alcohol or drug-use disorders and treatment history. |
I haven't published pass/fail numbers for blood pressure or diabetes here. Those details sit in the Medical Manual and your examiner's judgment, not in a single cutoff you can plan around.
Medications: what gets a closer look
Taking a prescribed medication doesn't automatically disqualify you. Medications are reported on the CG-719K, the medical form, not added to the CG-719B credential application just because you take them. On the CG-719K you list every prescription and nonprescription medication, supplement and vitamin filled, refilled or taken within 30 days of signing, or used for 30 days or more in the last 90, with the dose, frequency and condition treated CG-719K. See the medication checklist on Passing the CG-719K.
There's no simple "prohibited list." The Coast Guard looks at the medication together with the condition behind it, the dose, how stable you are, side effects and your duties. None of these categories is automatically disqualifying, but each may require additional medical review or documentation, so raise them early with your treating clinician:
| Category | Why it may matter at sea |
|---|---|
| Opioid pain medication | Alertness, judgment, coordination and reaction time |
| Sedatives and sleep medication | Leftover drowsiness and reduced alertness |
| Benzodiazepines and some anxiety medication | Thinking, coordination and fatigue risk |
| Stimulant medication | The condition treated, dose stability and side effects |
| Antiseizure medication | Review of the underlying seizure-related condition |
| Insulin and some diabetes medication | Blood-sugar control history and risk of sudden incapacitation |
| Anticoagulants | The underlying condition and operational risk |
| Certain psychiatric medication | The underlying diagnosis, functioning, stability and side effects |
Drug testing and medical fitness are separate questions. A valid prescription can matter when a Medical Review Officer reviews a drug-test result, but it doesn't show you're fit for safety-sensitive duties. The Coast Guard's Medical Division decides that, and your employer may have a stricter medication policy. A state medical-marijuana card is not a prescription for either purpose. See Drugs, Alcohol & DUI.
Medical information notice: Mariners Online does not provide medical advice and cannot determine whether a medication or medical condition is compatible with a Coast Guard medical certificate, safety-sensitive vessel duties, or a specific employer's policy. Do not discontinue or change prescribed medication without advice from the prescribing clinician. Use the current CG-719K instructions and seek individualized medical, occupational-health, or maritime-credential guidance when needed.
Tanker work: benzene medical surveillance and respirators
If you're headed for tank vessels, you may hear about a "benzene card." It isn't a Coast Guard license, and it isn't part of your Coast Guard medical certificate or your Tankerman endorsement. It's shorthand for proof that you're in a benzene medical-surveillance program, and not every tanker crewmember needs one.
Coverage depends on expected exposure. Under 46 CFR 197.560, a covered employee's program generally includes:
- An initial medical exam and occupational-exposure history
- A complete blood count, including white cells, red cells and platelets
- Annual follow-up exams
- A physician's written opinion noting any limits on benzene exposure or respirator use
It generally applies when expected exposure reaches the action level on 30 or more days a year, or exceeds a permissible exposure limit on 10 or more days a year. Wearing a respirator doesn't remove the surveillance requirement. Contractors and cargo inspectors who aren't crew have a separate written certification requirement, which the vessel's person in charge reviews 46 CFR 197.530.
What to do before you pay for training
Name the job and endorsement you're aiming for
A 100-ton captain, a deck officer, an engineer and an entry-level rating can face different standards. Know which one applies to you.
Book an exam with a clinician who knows mariner medicals
Use the current Coast Guard form for your application. The full CG-719K covers upgrades; the shorter CG-719K/E is for entry-level ratings only. See TWIC & First MMC.
Bring records and a complete medication list
Ask the examiner which specialist reports or extra tests the Coast Guard is likely to want for your history, and get them lined up.
Settle big questions before big, nonrefundable payments
A favorable opinion from your examiner is encouraging, but it isn't the Coast Guard's decision.
Check the school's and employer's rules too
Schools and employers can set their own medical and physical requirements on top of the Coast Guard's.
What a waiver is, and isn't
- It's a possible route to approval, not a promise. The Coast Guard grants waivers when objective medical evidence shows a condition is well enough controlled.
- It can come with strings. Periodic medical reports, monitoring, or limits on where and how you serve.
- Older guidance is out of date. NVIC 04-08 and NVIC 01-14 were superseded in 2019 by the Merchant Mariner Medical Manual. Use the manual and the current regulations.
Official sources
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