On July 1, 2026, three frontline warships from the Indian Navy Eastern Fleet quietly wrapped up a joint tactical exercise in the Gulf of Thailand. To the casual observer, the passing exercise, or PASSEX, alongside the Royal Thai Navy frigate HTMS Chao Phraya looked like standard maritime diplomacy.
It was anything but standard.
This deployment happened right at a time when power dynamics in the Indo-Pacific are shifting fast. Led by Rear Admiral Alok Ananda, the Flag Officer Commanding Eastern Fleet, the deployment of INS Udaygiri, INS Kavaratti, and INS Shakti to the naval base at Sattahip sends a loud message about India defense readiness and its growing role as a primary security provider in Southeast Asia.
Most news reports simply copy-pasted the official government press release. They told you the ships arrived, played some sports, and sailed away. They missed the real story. This operation represents a massive step forward for India updated maritime strategy, a doctrine known as MAHASAGAR, and it shows exactly how India intends to protect the vital sea lanes connecting the Indian Ocean to the Pacific.
The Technical Powerhouse Sent to Sattahip
When a country sends a naval flotilla to a foreign port, the specific mix of ships tells you exactly what they are trying to achieve. India did not just send older patrol craft for a friendly visit. They sent a highly capable task group that balances stealth, anti-submarine warfare, and long-range endurance.
INS Udaygiri and the Push for Surface Dominance
The centerpiece of the flotilla is INS Udaygiri, a Nilgiri-class stealth guided-missile frigate. Commissioned in August 2025, this ship represents the absolute front line of Indian naval modernization. It is the hundredth warship designed entirely by the Indian Navy Warship Design Bureau, a major point of pride for New Delhi.
With a displacement of over 6,600 tonnes, Udaygiri is packed with serious firepower. It carries 48 vertical launch cells for Barak 8 long-range surface-to-air missiles and another eight cells dedicated to BrahMos supersonic cruise missiles. This gives the ship the ability to strike targets on land or at sea from hundreds of kilometers away while maintaining a low radar profile due to its advanced structural geometry.
When you see Udaygiri operating in the Gulf of Thailand, you are looking at India ability to project high-end combat power far from its home waters in Visakhapatnam.
INS Kavaratti and the Silent Threat Under the Waves
Submarines are the ultimate threat in the shallow, crowded waters of Southeast Asia. That is why the inclusion of INS Kavaratti is so significant. Kavaratti is a Kamorta-class anti-submarine warfare corvette. It features an incredibly high percentage of indigenous components, sitting at roughly 90 percent Indian-made materials and weapons.
The hull is built with special high-tensile steel developed locally, and the ship structure uses advanced carbon composite materials to reduce its weight and radar signature. Kavaratti is equipped with the HUMSA-NG bow-mounted sonar system, rocket launchers, and torpedo tubes designed specifically to hunt down modern diesel-electric submarines. In the narrow choke points of the region, a dedicated submarine hunter is exactly what a task group needs to survive.
INS Shakti and the Reality of Deep Sea Operations
You can have the most advanced stealth frigates in the world, but they are useless if they run out of fuel or ammunition after a week at sea. This is where INS Shakti comes into play. Shakti is a Deepak-class fleet tanker capable of carrying over 15,000 tonnes of liquid cargo, including fuel oil and aviation fuel, alongside tons of ammunition and dry provisions.
Shakti allows the Eastern Fleet to stay at sea for months without needing to pull into a friendly port for supplies. By sending a fleet tanker along with a frigate and a corvette, India proved to the region that its fleet can sustain operations deep within Southeast Asian waters indefinitely.
Decoding the MAHASAGAR Doctrine
To understand why this visit happened now, you have to look at the big strategic picture. For years, India guided its maritime policy through an initiative called SAGAR, which stood for Security and Growth for All in the Region. It was a solid framework, but it focused mostly on the immediate neighborhood of the Indian Ocean.
That changed recently. India updated its strategic outlook with the introduction of the MAHASAGAR doctrine. The word itself translates to ocean in Hindi, signaling a major expansion in scale.
Instead of just looking at the waters directly off the coast of India, MAHASAGAR focuses on a broader maritime vision that stretches across the entire Indo-Pacific region, with a specific focus on supporting the Global South and building deep partnerships with ASEAN nations like Thailand.
This year, 2026, marks the ASEAN-India Year of Maritime Cooperation. The deployment of the Eastern Fleet task group is the physical manifestation of this policy. India wants to show its partners that it is not just talking about regional stability behind closed doors in New Delhi. It is actively deploying the hardware necessary to enforce it.
What Actually Happens During a PASSEX
The mainstream media loves to use the word PASSEX without ever explaining what the sailors are actually doing out there on the water. A passing exercise is an ad-hoc drill conducted when ships from two friendly navies find themselves in the same area. It requires zero long-term planning compared to massive war games like Malabar, making it a perfect tool for rapid tactical alignment.
During the drill with the Royal Thai Navy frigate HTMS Chao Phraya, the crews engaged in several complex maneuvers.
First, they practiced tactical communication. When an international crisis hits, navies must communicate instantly without language barriers or technical glitches slowing them down. The ships used standardized international signaling codes and secure communication channels to coordinate their movements.
Second, they focused on advanced formation steaming. This involves multiple large warships maneuvering at high speeds just a few hundred meters away from each other. It requires incredible precision from the bridge teams and tests the seamanship of everyone involved.
Third, these exercises frequently involve cross-deck helicopter operations. An Indian helicopter might land on the deck of a Thai warship, or vice versa. This builds a baseline level of familiarity. If a real disaster happens, such as a major typhoon or a maritime search and rescue emergency, the two navies can work together without skipping a beat.
The Geopolitical Context of the Andaman Sea
You cannot separate this naval drill from the geography of the region. Sattahip sits right on the edge of the Gulf of Thailand, just a short distance from the critical choke points of the Malacca Strait. Millions of barrels of oil and billions of dollars in global trade pass through these narrow waters every single day.
Thailand occupies a unique position because it borders both the Gulf of Thailand and the Andaman Sea. India maintains a major military command in the Andaman and Nicobar Islands, which sits right at the western entrance to the Malacca Strait. Therefore, India and Thailand are direct maritime neighbors sharing responsibility for one of the most heavily trafficked maritime corridors on earth.
As foreign military footprints expand in Southeast Asia, Thailand is working hard to balance its relationships with major world powers. By conducting regular, high-value naval interactions with India, Bangkok is diversifying its security options. India offers a powerful alternative partnership, one built on mutual respect, international law, and shared democratic values.
Moving Past Routine Port Calls
The Indian Navy strategy has clearly shifted away from purely symbolic port visits. In the past, a ship might visit a foreign port just to show the flag and host a formal dinner. Today, every single port call by the Eastern Fleet is packed with operational substance.
While docked at Sattahip from June 28 until their departure, the Indian crews did not just rest. They conducted deep professional exchanges with Thai naval officers. They shared data on maritime domain awareness, discussed strategies for countering piracy, and analyzed the growing threat of illegal, unreported, and unregulated fishing in the region.
They also organized community outreach events and sporting matches, which help build a foundation of trust between the younger sailors who will eventually rise through the ranks to lead these navies in the decades to come.
Next Steps for Indo-Thai Maritime Security
This PASSEX should not be viewed as an isolated event. It is part of a continuous process of building security ties in the Indo-Pacific. For these drills to remain useful, both nations need to take specific steps to capitalize on the momentum generated by the Eastern Fleet deployment.
- Navies must establish more permanent, automated data-sharing links to track commercial shipping and unidentified vessels moving through the Andaman Sea.
- Future exercises should move past basic passing maneuvers and incorporate complex anti-submarine training scenarios, using both Indian and Thai assets.
- The two nations should increase the frequency of coordinated patrols along their shared maritime boundary to deter transnational maritime crimes effectively.
The era of treating maritime security as a localized issue is completely over. The deployment of INS Udaygiri, INS Kavaratti, and INS Shakti shows that India understands its responsibilities under the MAHASAGAR doctrine. By consistently showing up in the waters of Southeast Asia, the Indian Navy is proving that it has the ships, the logistical stamina, and the political will to keep the sea lanes open and stable for everyone.
