Prime Day 2026 ran 23–26 June — inbound cutoffs were May 27 / June 5

What this taught the desk

Event PPC without event-ready inventory is how ACOS explodes in 96 hours. If units were still “in transit” on 23 June, the ranking campaign should already have been paused. The next clock is Prime Big Deal Days 6–7 October 2026 (About Amazon) and then Black Friday / Cyber Monday 27 / 30 Nov.

SOP for the next event

1. List hero ASINs. Confirm on-hand + inbound ETA against the published FC arrival dates.
2. Deal SKUs get a separate exact layer and a kill time. Do not blend them into evergreen auto.
3. Daypart budgets through the evening conversion window. Event CPCs die at 2pm if the cap is naive.
4. The day after: harvest, negate junk event queries, ease bids that only worked because of the badge.

What Amazon confirmed vs what sellers assumed

Prime Day 2026 ran four days, 23–26 June, starting 12:01 a.m. PDT — only the second June Prime Day after 2021. A lot of evergreen “early July” calendars were already wrong. Seller Central inbound tied to the event: 27 May for AWD and FBA minimal splits, 5 June for Amazon-optimized splits. Deal submission closed 26 May. Those dates are why ads into “in transit” inventory exploded ACOS: the badge was live, the FC was not, and CPC did not care.

How to read an event after the fact

Export search terms for 23–26 June only. Tag event junk vs converters you will still want in July. Negate the junk. Ease bids that only cleared because of the deal price. Check which ASINs stocked out mid-event — those ranking campaigns should have been paused, not “optimized.” Then copy the calendar math forward to Prime Big Deal Days 6–7 October: inbound is weeks earlier than the press page.

PPC structure that survives a 96-hour event

Deal SKUs get their own exact layer and a kill time. Do not blend Lightning / Best Deal traffic into evergreen auto. Daypart budgets through the evening conversion window; a naive daily cap dies at 2pm on day one and you miss the hours that convert. Brand defense stays on — rivals shop events. The day after is harvest, not a victory lap.

What not to do next time

• Raise bids on ASINs that missed FC arrival.
• Leave event campaigns running on 27 June “because it is still working.”
• Treat About Amazon’s consumer page as an inbound SOP. FC arrival dates live in Seller Central.

Related: Prime Big Deal Days 6–7 Oct, weekly harvest, operator calendar.

Copy the method, not the 2026 dates

Prime Day 2026 ran four days, 23–26 June, 12:01 a.m. PDT — only the second June Prime Day after 2021. Evergreen “early July” calendars were already wrong. Seller Central inbound tied to the event: 27 May for AWD and FBA minimal splits, 5 June for Amazon-optimized splits. Deal submission closed 26 May. Ads into “in transit” inventory exploded ACOS because the badge was live, the FC was not, and CPC did not care. After the event: export search terms for 23–26 June only, tag junk vs converters you will still want in July, negate the junk, ease bids that only cleared because of the deal price. Copy that method to Prime Big Deal Days. The calendar will move in 2027.