III Code — IMO Instruments Implementation Code

The IMO Instruments Implementation Code (III Code), adopted as Res. A.1070(28) in 2013 and made mandatory through SOLAS + MARPOL + Load Line + Tonnage + COLREG + STCW amendments effective 1 January 2016, is the single most consequential recent IMO instrument for flag-state accountability. It defines the flag, coastal, and port-state obligations under the mandatory IMO instruments, and — critically — subjects every Party to a compulsory audit by the IMO Member State Audit Scheme (IMSAS).

Structure of the Code

The III Code has three main parts:

Part 1 — Common areas. Overarching obligations applicable to all IMO Party states: implementation, delegation of authority, enforcement, review, and monitoring.
Part 2 — Flag State obligations. Detailed obligations to ensure that ships flying the state's flag comply with mandatory IMO instruments. Includes recognition of ROs (Recognised Organisations — the class societies delegated statutory authority), casualty investigation, and follow-up.
Part 3 — Coastal + Port State obligations. Obligations to ensure PSC + coastal-state enforcement of IMO instruments — cross-reference to the regional MoU regimes for practical enforcement.

Flag State obligations under Part 2

The Code lists specific flag-state obligations that expand on general SOLAS Ch. XI-2 requirements:

Ratification + implementation. Ratify + implement mandatory IMO instruments in domestic law.
Regulation. Establish + maintain regulatory framework covering ship + crew + equipment.
Delegation. Where authority is delegated to a Recognised Organisation, agreements must be documented + oversight maintained. RO Code (Res. MSC.349(92)) sets minimum RO requirements.
Enforcement. Take action against ships not complying — including detention where necessary + prosecution.
Casualty investigation. Investigate any casualty involving a ship flying the flag; publish reports to IMO GISIS + take corrective action.
Monitoring + review. Continuously monitor compliance + regularly review the effectiveness of the flag-state programme.

Coastal + Port State obligations under Part 3

Search + Rescue (SAR). Provide SAR services in accordance with SAR Convention.
Aids to navigation. Maintain lights + buoys + navigational marks per SOLAS V + IALA guidelines.
Port State Control. Inspect foreign-flag vessels in port + share results with regional MoUs + IMO Global Integrated Shipping Information System (GISIS).
Reception facilities. Provide adequate MARPOL waste-reception facilities.
Casualty response. Respond to casualties in territorial waters + EEZ.

IMO Member State Audit Scheme (IMSAS)

The IMSAS audit is the compliance-enforcement teeth of the III Code. Every IMO Member State must undergo a mandatory audit by an IMO-appointed team. Audit cycle: currently every 7 years for most states. The audit assesses conformity with the III Code across all three parts + all applicable IMO instruments.

Audit findings. Conformities, non-conformities, and observations — non-conformities require documented corrective action.
Confidentiality. Detailed audit findings are confidential; a summary is published in the IMO Ship Audit Scheme (MSAS) results.
Consequences. Failure to correct non-conformities can lead to loss of confidence + political consequences within the IMO Council election process.

Practical implications for shipowners + Masters

Flag-state choice. The III Code strengthens the case for flag registration with a robust administration. Smaller open registries with weak flag-state programmes are increasingly cited in PSC MoU targeting factors.
Casualty follow-up. The flag state must investigate every casualty. Masters + owners must cooperate + provide full information — Casualty Investigation Code (Res. MSC.255(84)) applies.
Certificate + endorsement recognition. Where a flag delegates statutory certification to a class society (RO), the certification must meet III Code + RO Code standards. Certificates from flags failing IMSAS audit face greater scrutiny.