WILLIAM MARRIN PHD
NPI 1861493629
Psychologist in Port Jefferson, NY

Active since August 02, 2005PECOS EnrolledAccepts Medicare Assignment
200 BELLE TERRE RD, PORT JEFFERSON, NY 11777(631) 474-6000 Get Directions Write a Review

NPPES record last updated: May 5, 2011. Verified against the NPPES registry weekly; last sync: November 01, 2026.

About William Marrin Phd NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

WILLIAM MARRIN PHD (NPI 1861493629) is an individual psychologist in Port Jefferson, New York, licensed in New York (008777) and active in the NPI registry since August 2005. He is enrolled in Medicare PECOS and is a graduate of Other (1984).

NPPES Registry Identity

NPI1861493629
Entity TypeIndividualMale
Primary Taxonomy103T00000X
Provider Legal NameWILLIAM MARRINCredential: PHD
Location Address200 BELLE TERRE RDPort Jefferson, NY 11777-1928
Mailing Address8 Manor RdSmithtown, NY 11787-2715 · (631) 265-4670
Sole ProprietorYes
Medical School CMSOtherGraduated 1984
Enumeration DateAugust 2, 2005
Last NPPES UpdateMay 5, 2011
✔ NPI 1861493629 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyPsychologistBehavioral Health & Social Service Providers
Taxonomy Code103T00000X
License✔ Licensed in NY · 008777
Definition
A psychologist is an individual who is licensed to practice psychology which is defined as the observation, description, evaluation, interpretation, and modification of human behavior by the application of psychological principles, methods, and procedures, for the purpose of preventing or eliminating symptomatic, maladaptive, or undesired behavior and of enhancing interpersonal relationships, work and life adjustment, personal effectiveness, behavioral health, and mental health. The practice of psychology includes, but is not limited to, psychological testing and the evaluation or assessment of personal characteristics, such as intelligence, personality, abilities, interests, aptitudes, and neuropsychological functioning; counseling, psychoanalysis, psychotherapy, hypnosis, biofeedback, and behavior analysis and therapy; diagnosis and treatment of mental and emotional disorder or disability, alcoholism and substance abuse, disorders of habit or conduct, as well as of the psychological aspects of physical illness, accident, injury, or disability; and psycheducational evaluation, therapy, remediation, and consultation. Psychological services may be rendered to individuals, families, groups and the public.
200 BELLE TERRE RD, Port Jefferson, NY 11777

Other Identifiers 1

Medicare UPINV61831NY

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

William Marrin Phd is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID5092744276
PECOS Enrollment IDI20050808000959
Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment– Home Health Agency– Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignment

Medicare enrollment records show William Marrin reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

General Acute Care Hospital
200 BELLE TERRE RD
Port Jefferson, NY 11777
  • Reassigned Medicare billing, New York enrollment
  • 210 clinicians in this Medicare group

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

Emergency Medicine
200 BELLE TERRE RD
PORT JEFFERSON, NY 11777
Audiologist-Hearing Aid Fitter
200 BELLE TERRE RD
PORT JEFFERSON, NY 11777
Physical Therapist
200 BELLE TERRE RD
PORT JEFFERSON, NY 11777
Occupational Therapist (Pediatrics)
200 BELLE TERRE RD
PORT JEFFERSON, NY 11777
Physician Assistant
200 BELLE TERRE RD
PORT JEFFERSON, NY 11777
Pediatrics
200 BELLE TERRE RD
PORT JEFFERSON, NY 11777
Physician Assistant
200 BELLE TERRE RD
PORT JEFFERSON, NY 11777
Pharmacist
200 BELLE TERRE RD
PORT JEFFERSON, NY 11777

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is William Marrin's NPI number?

The NPI number for William Marrin is 1861493629. It was assigned to this individual provider in the NPPES registry on August 2, 2005.

Where is William Marrin located?

William Marrin practices at 200 Belle Terre Rd, Port Jefferson, NY 11777. The listed phone number is (631) 474-6000.

What is William Marrin's specialty?

The primary specialty registered for this NPI is Psychologist with taxonomy code 103T00000X.

Is William Marrin enrolled in Medicare?

Yes. William Marrin is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

Which organization bills Medicare for William Marrin's services?

According to the CMS Revalidation Reassignment List (October 2026 release), William Marrin reassigns Medicare benefits to St. Charles Hospital Corp. (Port Jefferson, NY). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for William Marrin's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

When was this NPI record last updated?

The NPPES record for William Marrin was last updated on May 5, 2011. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 15 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.