Company: FWRG
Filing Date: 2025-08-07
Form Type: 424B3
Source: 0001628280-25-038995
Chunk: 0

Company: First Watch Restaurant Group, Inc.
Filing Date: 2025-08-07
Form: 424B3
Chunk 0
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#### Filed Pursuant to Rule 424(b)(3)

#### Registration No. 333-268197

#### Prospectus supplement
(To prospectus dated November 7, 2022)

#### First Watch Restaurant Group, Inc.
<div align='center'>5,000,000 Shares of Common Stock Offered by Selling Stockholders</div>

The selling stockholders identified in this prospectus supplement are offering 5,000,000 shares of our common stock. We are not selling any shares under this prospectus supplement and will not receive any proceeds from the sale of shares by the selling stockholders. Our common stock is listed on the Nasdaq Global Select Market (“Nasdaq”) under the symbol “FWRG.” On August 6, 2025, the last sale price of our common stock as reported on Nasdaq was $18.83 per share.

Investing in our common stock involves risk. See “

#### Risk Factors

#### ” on page

#### S-9
of this prospectus supplement to read about factors you should consider before buying shares of our common stock.

Neither the Securities and Exchange Commission (the “SEC”) nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The underwriters have agreed to purchase our common stock from the selling stockholders at a price of $17.70 per share, which will result in $88.5 million of proceeds to the selling stockholders before expenses. The selling stockholders will receive all of the proceeds from this offering.

The underwriters may offer the shares of common stock from time to time for sale in one or more transactions on Nasdaq, in the over-the-counter market, through negotiated transactions or otherwise at market prices prevailing at the time of sale, at prices related to prevailing market prices or at negotiated prices. See “Underwriting” for additional information regarding underwriters compensation.

The underwriters expect to deliver the shares of common stock against payment in New York, New York on August 8, 2025.

| Barclays |     | Goldman Sachs & Co. LLC |

<div align='center'>The date of this prospectus supplement is August 6, 2025.</div>

### TABLE OF CONTENTS

#### Prospectus Supplement
| ABOUT THIS PROSPECTUS SUPPLEMENT                                                    |     | S-1  |
| PROSPECTUS SUPPLEMENT SUMMARY                                                       |     | S-