Duty / PE to the U.S.: hard copies of travel orders; see Travel Documentation.pdf on the AMC page (orders with CIC, ID and passport; dependents 10+ ID; RED/DA when traveling with dependents; contractors LOA; etc.).
Space-A: NAVCENT coordinator package ≥15 working days out, plus DoDI 4515.13 eligibility, and print or digital copy at the counter.
Entry / FCG: CNIC NSA Bahrain PCS page (search-indexed official): all active duty need an official (no-fee) passport before arrival; Kingdom of Bahrain requires a visa; check the DoD Foreign Clearance Guide. Dependents cannot enter on ID and orders alone (Welcome Aboard / CNIC language). AMC page also links APACS for travel to Diego Garcia (NSFDGAdminofficer@fe.navy.mil) — that is a DG onward requirement, not Bahrain entry.
Dress (official, not a blog): AMC PE banner — no military uniform into BIA. CNIC Policies and Guidance + NSA instruction 10120.1G (Military and Civilian Personnel Clothing Policy): applies to military, DoD, contractors, and family members over 13, visiting or assigned. On-base civilian attire must not include frayed/cut-off/torn clothing, offensive slogans (including alcohol/drug promotion), or (for U.S. military, except Muslim-faith members) native thobe/guttra/abaya. Off-installation clothing is per the referenced higher-headquarters order (CNIC: COMUSNAVCENT/COMFIFTHFLT OPORD 1000-10 (U) for attached Navy personnel and families). Confirm current instruction before you pack.
Alcohol (official, not the AMC HTML): NAVSUP Bahrain country instructions list alcoholic beverages among prohibited import items (HHG/country list). SECNAV overseas Bahrain pamphlet: NEX alcohol ration system is governed by NSA instruction; newcomers register at NEX customer service with orders and military ID. AMC page does not print a PE liquor allowance. Do not pack alcohol in PE bags expecting it to clear BIA.