Battlefield 6: what “Tidal Wave” brings on September 15, 2026 — the “20,000 Leagues Under the Sea Collection” event, proximity chat, and the Phantom program

Season 4 of Battlefield 6 and REDSEC closes out with a third and final phase, dated Tuesday, September 15, 2026. It's called "Tidal Strike", and Electronic Arts' roadmap headlines it: "TIDAL STRIKE ARRIVES SEPTEMBER 15".

Four workstreams are attached to it: a collection event, "several Portal updates", the debut of proximity chat, and the Phantom program challenge. No single official page describes all of them.

Four official sources, four levels of information

The French name of the collection event is "Collection 6 lieues sous les mers". It doesn't appear anywhere in EA's running text. It only shows up in two places, in two different forms: the "TIDAL STRIKE" box on the season 4 page, and the roadmap infographic, which reads "6 LIEUES SOUS LES MERS: COLLECTION EVENT". The English versions say Deep Six Collection Event and DEEP SIX: COLLECTION EVENT.

Two details round out the picture. On the French page, the title is translated but the section anchor remains #tidal-strike. And the two labels don't tell the same story: "Deep Six" refers to permanently sinking something, while "6 lieues sous les mers" evokes Jules Verne — this is our reading; EA never comments on its localization choices. Keep the French form in mind: "Tidal Strike" doesn't officially exist in France.

The collection event: a knife, and nothing else named

The roadmap is the only source to mention a reward: "Marked by a collection event where you'll be able to earn the Royal Navy diving knife, this major update will include several Portal updates and two major additions to REDSEC". Its infographic shortens this to "diving knife" and describes it as a "new melee weapon", under a dual "Battlefield 6 | REDSEC" label. The season page, meanwhile, names no item at all:

Retrieve. Achieve. Conquer. In the final phase of Season 4, take part in tactical missions across Battlefield 6 and REDSEC to earn in-game items during the "Deep Six Collection" event.

Three pieces of information stand out: the event covers both games, it involves tactical missions, and the infographic announces "new challenges". Playtime alone won't be enough. Everything else is missing — end date, number of challenges, list of items.

No page announces a dedicated currency either, and the break with the previous phase is clear-cut: for Top Gun, the 1.4.2.0 patch notes promised "elite medals, a time-limited currency that can be spent on cosmetic items". So reading elsewhere that the "6 Leagues Under the Sea Collection" works with a currency is not sourced.

Proximity chat: Battle Royale only, and under test label

This is the only element from phase 3 that the July 30 community update covers: "The first iteration of proximity chat will arrive with season 4 phase 3, Tidal Wave, on September 15 via Battlefield Labs in-game. It will initially be available in Battle Royale". Multiplayer will come "at a later date", with no timeline given.

The studio also publishes what it intends to measure: "audio range and clarity, player controls, moderation tools, and the feature's broader effect on the flow of a match". Moderation is therefore to be evaluated, not a given.

Some vocabulary wobbling complicates research: the English text everywhere writes Battlefield Labs in Live, but the roadmap speaks of a "live Battlefield Labs experience" while the community update writes "Battlefield Labs in-game" three times, then "live" once.

Phantom Program: challenges, but unlocked by Easter eggs

The roadmap stays vague: "the Phantom Program challenge, where only the most deserving will be able to gather information to reconstruct a powerful access code and take advantage of Fort Lyndon's security system". The infographic adds "new secrets to discover".

The concrete answer comes from the July 30 Discord Q&A session. Challenges to chain together or secrets to hunt down? Battlefield Studios answers: "It's a mix of both! The system is challenge-based, but to unlock or complete them, you'll need to track down and find Easter Eggs across Fort Lyndon." So part of the content unlocks by exploring the map.

Two naming pitfalls follow. EA can't seem to settle on one: "Phantom Program challenge" in the roadmap, "the Phantom Program event" on Discord, "PHANTOM PROGRAM" alone on the infographic. And the community update writes "Fort Lyndon" then "Fort Lydon" a few paragraphs later — a typo carried over from the English text and copied by the translation.

One last point to avoid confusion: Battlefield 6 is also sold as a Phantom Edition, at €99.99 versus €69.99 for the Standard Edition. It has no connection whatsoever to the Phantom program, and EA states nowhere that one grants access to the other.

Optics and Portal: two promises still empty

On the weapons side, the roadmap promises only one thing, without detail: "stay tuned for more information on the new optic attachment choices coming with the final phase of Season 4, Tidal Wave." No name, no number, and the infographic says nothing about it. The two mid-season attachments promised "later this season," the angled vertical grip and the hybrid suppressor, appear neither in the 1.4.2.0 patch notes from August 18, nor in the 1.4.2.5 patch notes from September 1.

On the Portal side, "several updates" are announced without a single word of detail. Two projects dated "later during Season 4" appear on Discord: adjusting the water level on naval maps, and bringing "all Season 4 maps to ranked and custom modes." The connection between the two is our own.

At what time? EA hasn't published it

No official source gives a time for September 15, and the season's two previous phases don't give the same answer.

CEST matches Paris time until the end-of-October clock change: these times can be read as they are. EA also adds, on August 18: "Times listed may vary and are subject to change." The 1.4.2.5 update, rolled out on September 1, says not a word about phase 3.

What to remember

Of the four projects for September 15, only one is described precisely (proximity chat), only one has a named reward (the diving knife), the Phantom program has a known operating method but no public content, and Portal has nothing published. The roadmap only states that Season 4 "will continue until the end of summer."

Tidal Wave falls about three weeks before the first anniversary of Battlefield 6, released on October 10, 2025. It's the last delivery before Season 5, announced for winter with Sections, the server browser, multiplayer rankings, and three new maps.

In practice: finish the Season 4 Battle Pass, "over 100 tiers," without waiting for a closing date that has never been published. And if the diving knife interests you, set aside time on Battlefield 6 and on REDSEC.