<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE BALANCE
SHEET AND INCOME STATEMENT OF TYCOM LTD. AS OF AND FOR THE FISCAL YEAR ENDED
SEPTEMBER 30, 2000 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 12-MOS
<FISCAL-YEAR-END> SEP-30-2000
<PERIOD-START> OCT-01-1999
<PERIOD-END> SEP-30-2000
<CASH> 91,000
<SECURITIES> 0
<RECEIVABLES> 373,600
<ALLOWANCES> 47,800
<INVENTORY> 129,500
<CURRENT-ASSETS> 2,891,500
<PP&E> 796,900
<DEPRECIATION> 203,800
<TOTAL-ASSETS> 4,088,300
<CURRENT-LIABILITIES> 1,200,600
<BONDS> 653,500
0
0
<COMMON> 130,100
<OTHER-SE> 2,031,400
<TOTAL-LIABILITY-AND-EQUITY> 4,088,300
<SALES> 2,539,700
<TOTAL-REVENUES> 2,539,700
<CGS> 1,840,700
<TOTAL-COSTS> 1,840,700
<OTHER-EXPENSES> 0
<LOSS-PROVISION> 35,700
<INTEREST-EXPENSE> 45,900
<INCOME-PRETAX> 495,700
<INCOME-TAX> 182,900
<INCOME-CONTINUING> 303,300
<DISCONTINUED> 0
<EXTRAORDINARY> 0
<CHANGES> 0
<NET-INCOME> 303,300
<EPS-BASIC> 0.66
<EPS-DILUTED> 0.66
</TABLE>