diff --git a/.changeset/vast-buses-see.md b/.changeset/vast-buses-see.md
new file mode 100644
index 000000000..683a3bf3c
--- /dev/null
+++ b/.changeset/vast-buses-see.md
@@ -0,0 +1,5 @@
+---
+'mermaid': minor
+---
+
+chore: Update packet diagram to use new class-based database structure
diff --git a/packages/mermaid/src/diagrams/packet/db.ts b/packages/mermaid/src/diagrams/packet/db.ts
index d7b550472..863bd79e1 100644
--- a/packages/mermaid/src/diagrams/packet/db.ts
+++ b/packages/mermaid/src/diagrams/packet/db.ts
@@ -1,6 +1,7 @@
 import { getConfig as commonGetConfig } from '../../config.js';
 import type { PacketDiagramConfig } from '../../config.type.js';
 import DEFAULT_CONFIG from '../../defaultConfig.js';
+import type { DiagramDB } from '../../diagram-api/types.js';
 import { cleanAndMerge } from '../../utils.js';
 import {
   clear as commonClear,
@@ -11,49 +12,42 @@ import {
   setAccTitle,
   setDiagramTitle,
 } from '../common/commonDb.js';
-import type { PacketDB, PacketData, PacketWord } from './types.js';
-
-const defaultPacketData: PacketData = {
-  packet: [],
-};
-
-let data: PacketData = structuredClone(defaultPacketData);
-
+import type { PacketWord } from './types.js';
 const DEFAULT_PACKET_CONFIG: Required<PacketDiagramConfig> = DEFAULT_CONFIG.packet;
 
-const getConfig = (): Required<PacketDiagramConfig> => {
-  const config = cleanAndMerge({
-    ...DEFAULT_PACKET_CONFIG,
-    ...commonGetConfig().packet,
-  });
-  if (config.showBits) {
-    config.paddingY += 10;
+export class PacketDB implements DiagramDB {
+  private packet: PacketWord[] = [];
+
+  public getConfig() {
+    const config = cleanAndMerge({
+      ...DEFAULT_PACKET_CONFIG,
+      ...commonGetConfig().packet,
+    });
+    if (config.showBits) {
+      config.paddingY += 10;
+    }
+    return config;
   }
-  return config;
-};
 
-const getPacket = (): PacketWord[] => data.packet;
-
-const pushWord = (word: PacketWord) => {
-  if (word.length > 0) {
-    data.packet.push(word);
+  public getPacket() {
+    return this.packet;
   }
-};
 
-const clear = () => {
-  commonClear();
-  data = structuredClone(defaultPacketData);
-};
+  public pushWord(word: PacketWord) {
+    if (word.length > 0) {
+      this.packet.push(word);
+    }
+  }
 
-export const db: PacketDB = {
-  pushWord,
-  getPacket,
-  getConfig,
-  clear,
-  setAccTitle,
-  getAccTitle,
-  setDiagramTitle,
-  getDiagramTitle,
-  getAccDescription,
-  setAccDescription,
-};
+  public clear() {
+    commonClear();
+    this.packet = [];
+  }
+
+  public setAccTitle = setAccTitle;
+  public getAccTitle = getAccTitle;
+  public setDiagramTitle = setDiagramTitle;
+  public getDiagramTitle = getDiagramTitle;
+  public getAccDescription = getAccDescription;
+  public setAccDescription = setAccDescription;
+}
diff --git a/packages/mermaid/src/diagrams/packet/diagram.ts b/packages/mermaid/src/diagrams/packet/diagram.ts
index a73a77c05..84a7bca8f 100644
--- a/packages/mermaid/src/diagrams/packet/diagram.ts
+++ b/packages/mermaid/src/diagrams/packet/diagram.ts
@@ -1,12 +1,14 @@
 import type { DiagramDefinition } from '../../diagram-api/types.js';
-import { db } from './db.js';
+import { PacketDB } from './db.js';
 import { parser } from './parser.js';
 import { renderer } from './renderer.js';
 import { styles } from './styles.js';
 
 export const diagram: DiagramDefinition = {
   parser,
-  db,
+  get db() {
+    return new PacketDB();
+  },
   renderer,
   styles,
 };
diff --git a/packages/mermaid/src/diagrams/packet/packet.spec.ts b/packages/mermaid/src/diagrams/packet/packet.spec.ts
index b03ffe4d1..fd7b3211a 100644
--- a/packages/mermaid/src/diagrams/packet/packet.spec.ts
+++ b/packages/mermaid/src/diagrams/packet/packet.spec.ts
@@ -1,24 +1,26 @@
 import { it, describe, expect } from 'vitest';
-import { db } from './db.js';
+import { PacketDB } from './db.js';
 import { parser } from './parser.js';
 
-const { clear, getPacket, getDiagramTitle, getAccTitle, getAccDescription } = db;
-
 describe('packet diagrams', () => {
+  let db: PacketDB;
   beforeEach(() => {
-    clear();
+    db = new PacketDB();
+    if (parser.parser) {
+      parser.parser.yy = db;
+    }
   });
 
   it('should handle a packet-beta definition', async () => {
     const str = `packet-beta`;
     await expect(parser.parse(str)).resolves.not.toThrow();
-    expect(getPacket()).toMatchInlineSnapshot('[]');
+    expect(db.getPacket()).toMatchInlineSnapshot('[]');
   });
 
   it('should handle a packet definition', async () => {
     const str = `packet`;
     await expect(parser.parse(str)).resolves.not.toThrow();
-    expect(getPacket()).toMatchInlineSnapshot('[]');
+    expect(db.getPacket()).toMatchInlineSnapshot('[]');
   });
 
   it('should handle diagram with data and title', async () => {
@@ -29,10 +31,10 @@ describe('packet diagrams', () => {
     0-10: "test"
     `;
     await expect(parser.parse(str)).resolves.not.toThrow();
-    expect(getDiagramTitle()).toMatchInlineSnapshot('"Packet diagram"');
-    expect(getAccTitle()).toMatchInlineSnapshot('"Packet accTitle"');
-    expect(getAccDescription()).toMatchInlineSnapshot('"Packet accDescription"');
-    expect(getPacket()).toMatchInlineSnapshot(`
+    expect(db.getDiagramTitle()).toMatchInlineSnapshot('"Packet diagram"');
+    expect(db.getAccTitle()).toMatchInlineSnapshot('"Packet accTitle"');
+    expect(db.getAccDescription()).toMatchInlineSnapshot('"Packet accDescription"');
+    expect(db.getPacket()).toMatchInlineSnapshot(`
       [
         [
           {
@@ -52,7 +54,7 @@ describe('packet diagrams', () => {
     11: "single"
     `;
     await expect(parser.parse(str)).resolves.not.toThrow();
-    expect(getPacket()).toMatchInlineSnapshot(`
+    expect(db.getPacket()).toMatchInlineSnapshot(`
       [
         [
           {
@@ -78,7 +80,7 @@ describe('packet diagrams', () => {
     +16: "word"
     `;
     await expect(parser.parse(str)).resolves.not.toThrow();
-    expect(getPacket()).toMatchInlineSnapshot(`
+    expect(db.getPacket()).toMatchInlineSnapshot(`
       [
         [
           {
@@ -104,7 +106,7 @@ describe('packet diagrams', () => {
     +16: "word"
     `;
     await expect(parser.parse(str)).resolves.not.toThrow();
-    expect(getPacket()).toMatchInlineSnapshot(`
+    expect(db.getPacket()).toMatchInlineSnapshot(`
       [
         [
           {
@@ -130,7 +132,7 @@ describe('packet diagrams', () => {
     11-90: "multiple"
     `;
     await expect(parser.parse(str)).resolves.not.toThrow();
-    expect(getPacket()).toMatchInlineSnapshot(`
+    expect(db.getPacket()).toMatchInlineSnapshot(`
       [
         [
           {
@@ -172,7 +174,7 @@ describe('packet diagrams', () => {
     17-63: "multiple"
     `;
     await expect(parser.parse(str)).resolves.not.toThrow();
-    expect(getPacket()).toMatchInlineSnapshot(`
+    expect(db.getPacket()).toMatchInlineSnapshot(`
       [
         [
           {
diff --git a/packages/mermaid/src/diagrams/packet/parser.ts b/packages/mermaid/src/diagrams/packet/parser.ts
index 1dcccd636..689d86fb3 100644
--- a/packages/mermaid/src/diagrams/packet/parser.ts
+++ b/packages/mermaid/src/diagrams/packet/parser.ts
@@ -3,12 +3,12 @@ import { parse } from '@mermaid-js/parser';
 import type { ParserDefinition } from '../../diagram-api/types.js';
 import { log } from '../../logger.js';
 import { populateCommonDb } from '../common/populateCommonDb.js';
-import { db } from './db.js';
+import { PacketDB } from './db.js';
 import type { PacketBlock, PacketWord } from './types.js';
 
 const maxPacketSize = 10_000;
 
-const populate = (ast: Packet) => {
+const populate = (ast: Packet, db: PacketDB) => {
   populateCommonDb(ast, db);
   let lastBit = -1;
   let word: PacketWord = [];
@@ -91,9 +91,17 @@ const getNextFittingBlock = (
 };
 
 export const parser: ParserDefinition = {
+  // @ts-expect-error - PacketDB is not assignable to DiagramDB
+  parser: { yy: undefined },
   parse: async (input: string): Promise<void> => {
     const ast: Packet = await parse('packet', input);
+    const db = parser.parser?.yy;
+    if (!(db instanceof PacketDB)) {
+      throw new Error(
+        'parser.parser?.yy was not a PacketDB. This is due to a bug within Mermaid, please report this issue at https://github.com/mermaid-js/mermaid/issues.'
+      );
+    }
     log.debug(ast);
-    populate(ast);
+    populate(ast, db);
   },
 };