The following highways are numbered 343:

Australia

- Local Bendigo Highway

Canada

• Manitoba Provincial Road 343
• Newfoundland and Labrador Route 343
• Prince Edward Island Route 343
• Quebec Route 343
• Saskatchewan Highway 343

Japan

• Japan National Route 343

United States

• Connecticut Route 343
• County Road 343 (Levy County, Florida)
• Georgia State Route 343 (former)
• Louisiana Highway 343
• Maryland Route 343
• M-343 (Michigan highway)
• New York:
  • New York State Route 343
  • County Route 343 (Erie County, New York)
• North Carolina Highway 343
• Ohio State Route 343
• Pennsylvania Route 343
• Puerto Rico Highway 343
• Tennessee State Route 343
• Texas:
  • Texas State Highway 343 (former)
  • Texas State Highway Loop 343
• Virginia State Route 343
• Wyoming Highway 343