<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM CONSOLIDATED
FINANCIAL STATEMENTS AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
<CIK> 0001116086
<NAME> NEON COMMUNICATIONS, INC.
<S> <C>
<PERIOD-TYPE> 3-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-START> JUL-01-2000
<PERIOD-END> SEP-30-2000
<CASH> 40,318,924
<SECURITIES> 24,169,717
<RECEIVABLES> 2,739,488
<ALLOWANCES> (257,292)
<INVENTORY> 0
<CURRENT-ASSETS> 67,896,262
<PP&E> 154,191,913
<DEPRECIATION> (12,912,154)
<TOTAL-ASSETS> 276,317,560
<CURRENT-LIABILITIES> 36,102,546
<BONDS> 180,000,000
0
0
<COMMON> 187,539
<OTHER-SE> 51,381,970
<TOTAL-LIABILITY-AND-EQUITY> 276,317,560
<SALES> 4,221,289
<TOTAL-REVENUES> 4,221,289
<CGS> 2,849,806
<TOTAL-COSTS> 2,849,806
<OTHER-EXPENSES> 7,929,164
<LOSS-PROVISION> 0
<INTEREST-EXPENSE> 5,287,652
<INCOME-PRETAX> (10,742,138)
<INCOME-TAX> 0
<INCOME-CONTINUING> (10,742,138)
<DISCONTINUED> 0
<EXTRAORDINARY> 0
<CHANGES> 0
<NET-INCOME> (10,742,138)
<EPS-BASIC> (.63)
<EPS-DILUTED> (.63)
</TABLE>