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Record of Decision(s) for the Hawaii-California Training and Testing EIS/OEIS Now Available

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Fact Sheet

Project Overview Fact Sheet

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Welcome

Welcome to the United States (U.S.) Department of the Navy's Hawaii-California Training and Testing (HCTT) environmental planning website.

This website is a resource for information on the HCTT Environmental Impact Statement/Overseas Environmental Impact Statement (EIS/OEIS), which includes an assessment of the potential environmental effects associated with the Proposed Action to conduct at-sea military readiness activities within the HCTT Study Area (referred to as the “Study Area”). To meet training and testing requirements, the Department of the Navy (Navy) (including both the U.S. Navy and the U.S. Marine Corps), as the lead agency, jointly with the U.S. Coast Guard, U.S. Army, and U.S. Air Force, released a Final EIS/OEIS on Oct. 3, 2025. The Final EIS/OEIS includes an analysis of the potential environmental effects associated with at-sea training and testing activities, and the modernization and sustainment of ranges (collectively referred to as “military readiness activities”) within the HCTT Study Area.

On Dec. 2, 2025, the military services announced their decision to conduct at-sea military readiness activities as identified in the Final EIS/OEIS. After carefully weighing the strategic, operational, and environmental consequences of the Proposed Action, and considering public, stakeholder (including Native Hawaiian Organizations), and tribal input, Alternative 1 was selected as it best meets the current and future military readiness needs to meet national defense missions. 

Record of Decision(s) have been prepared by each military service and will be available for viewing on the project website.

The military services committed to the maximum level of mitigation measures that are beneficial and practical to implement under the Proposed Action and that are intended to avoid, minimize, or mitigate potential environmental effects during military readiness activities. 

The HCTT EIS/OEIS helps the Navy and other U.S. military services meet their environmental compliance requirements, while ensuring military readiness by:

  • Supporting current and future training and testing requirements
  • Allowing training and testing over greater distances, as larger areas are needed to train and test with new weapons required for countering new threats
  • Supporting increased training with unmanned systems
  • Increasing flexibility in conducting training and testing activities
  • Supporting modernizing and sustaining range capabilities
  • Updating environmental analyses using the best available science and analytical methods
  • Supporting Marine Mammal Protection Act and Endangered Species Act consultations for the reissuance of federal regulatory permits and authorizations within the Study Area.

The completion of the Final EIS/OEIS follows years of data gathering, analysis, stakeholder and tribal engagement, and public involvement. The military services held three in-person Draft EIS/OEIS public meetings and a virtual public meeting in 2025 and obtained stakeholder and tribal input at several stages during the environmental planning process. The Final EIS/OEIS includes responses to comments received on the Draft EIS/OEIS.

The Final EIS/OEIS includes an analysis of at-sea military readiness activities using new information, including an updated acoustic analysis, updated marine mammal density data, and evolving and emergent best available science. Proposed military readiness activities are similar to those analyzed in the 2018 Hawaii-Southern California Training and Testing (HSTT) EIS/OEIS (“Phase III” analysis) and the at-sea activities in the 2022 Point Mugu Sea Range (PMSR) EIS/OEIS and are consistent with activities conducted off Hawaii and California for more than 80 years. Training and testing activities that include the use of active sonar, explosives, or other sources of underwater sound would employ mitigation measures intended to reduce or avoid adverse effects on marine species.

Additional project information can be found in the project overview video and Project Materials page.

HCTT Study Area

The HCTT Study Area (see Figure 1) consists primarily of the Hawaii Study Area, the California Study Area, and the transit corridor connecting the two (see Figures 1-4). The Study Area includes the at-sea components of the range complexes (Hawaii Range Complex, Southern California [SOCAL] Range Complex, PMSR, Northern California [NOCAL] Range Complex), Navy pierside locations and port transit channels, bays, harbors, inshore waterways, amphibious approach lanes, and civilian ports where training and testing activities occur. For this EIS/OEIS, “at-sea components” include the marine environment around San Nicolas Island in Southern California and the Pacific Missile Range Facility in Hawaii where marine mammals (e.g., California sea lion, harbor seal, northern elephant seal, Hawaiian monk seal) haul out on the shoreline. Noise from missile and target launches and artillery firing from these two locations are analyzed in the Final EIS/OEIS to estimate potential effects on hauled-out pinnipeds.

The HCTT Study Area (for this “Phase IV” analysis) differs from the 2018 HSTT Study Area (for the “Phase III” analysis) in that it includes (see Figure 5):

  • An expanded SOCAL Range Complex
  • Special use airspace (Proposed Warning Area [W]-293 and Proposed W-294) corresponding to the expanded SOCAL Range Complex
  • New testing sea space between Proposed W-293 and PMSR
  • Two existing training and testing at-sea ranges, the PMSR and NOCAL Range Complex
  • Areas along the Southern California coastline from approximately Dana Point to Port Hueneme
  • Four amphibious approach lanes providing land access from the NOCAL Range Complex and PMSR

Figure 1. HCTT Study Area

The Hawaii-California Training and Testing Study Area. 
Click to enlarge

This is an image of a map providing an overview of the Hawaii-California Training and Testing Study Area. The map is showing the Hawaii Study Area, including the Hawaii Range Complex and Temporary Operating Area; the California Study Area; and the transit corridor connecting the two.

 

Figure 2. Hawaii Study Area

While the overall boundaries of the Hawaii Study Area have not changed from the 2018 analysis, nearshore areas, such as Kaneohe Bay or Marine Corps Training Area Bellows, are proposed to be used more frequently or for new training or testing activities, such as mine warfare training. 
Click to enlarge

This is an image of a map showing the Hawaii Study Area, including the Temporary Operating Area and Hawaii Range Complex boundary.

 

Figure 3. Oahu Portion of the Hawaii Range Complex

Hawaii Range Complex - Oahu
Click to enlarge

This is an image showing the Oahu portion of the Hawaii Range Complex, including the Fleet Operational Readiness Accuracy Check Site, the Shipboard Electronic Systems Evaluation Facility, amphibious maneuver areas, military installations and areas, non-explosive mine warfare training areas, and explosive mine warfare training areas.

 

Figure 4. Kauai Portion of the Hawaii Range Complex

Hawaii Range Complex - Kauai
Click to enlarge

This is an image showing the Kauai portion of the Hawaii Range Complex, including the Shallow Water Training Range, Barking Sands Tactical Underwater Range, Barking Sands Underwater Range Expansion, military installations and areas, non-explosive mine warfare training areas, restricted airspace, and warning areas.

 

Figure 5. Changes to the California Study Area since 2018

Areas outlined in yellow show the changes to the California Study Area from the 2018 HSTT Study Area (Phase III analysis) to the HCTT Study Area (Phase IV analysis). 
Click to enlarge

This is an image of a map showing the changes to the California Study Area from the 2018 Hawaii-Southern California Training and Testing Study Area (Phase III analysis) to the Hawaii-California Training and Testing Study Area (Phase IV analysis). The figure shows the Northern California Range Complex, Point Mugu Sea Range, Southern California Range Complex, the proposed Warning Area-293 and the proposed Warning Area-294, and amphibious approach lanes.

 

Hawaii-California Training and Testing Overview