<TABLE> <S> <C>

<PAGE>

<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS FINANCIAL INFORMATION EXTRACTED FROM THE CONSOLIDATED
FINANCIAL STATEMENTS OF WESTOWER CORPORATION FOR THE THREE AND SIX-MONTH PERIOD
ENDED MARCH 31, 1999 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
DOCUMENTS.
</LEGEND>

<S>                             <C>                     <C>
<PERIOD-TYPE>                   6-MOS<F1>               6-MOS<F1>
<FISCAL-YEAR-END>                          SEP-30-1999             SEP-30-1998
<PERIOD-START>                              OCT-1-1998              OCT-1-1997
<PERIOD-END>                               MAR-31-1999             MAR-31-1998
<CASH>                                       9,246,000               6,409,000
<SECURITIES>                                         0                       0
<RECEIVABLES>                               16,711,000               6,730,000
<ALLOWANCES>                                         0                       0
<INVENTORY>                                  2,920,000               1,269,000
<CURRENT-ASSETS>                            36,847,000              17,631,000
<PP&E>                                      32,887,000               5,892,000
<DEPRECIATION>                               2,358,000               1,525,000
<TOTAL-ASSETS>                             106,662,000              24,166,000
<CURRENT-LIABILITIES>                                0               7,578,000
<BONDS>                                     48,067,000                 806,000
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                        84,000                  61,000
<OTHER-SE>                                  44,816,000<F2>          13,644,000<F3>
<TOTAL-LIABILITY-AND-EQUITY>               106,662,000              24,166,000
<SALES>                                              0                       0
<TOTAL-REVENUES>                            43,271,000              23,358,000
<CGS>                                                0                       0
<TOTAL-COSTS>                               30,730,000              17,050,000
<OTHER-EXPENSES>                             9,793,000               3,448,000
<LOSS-PROVISION>                                     0                       0
<INTEREST-EXPENSE>                           1,123,000                  72,000
<INCOME-PRETAX>                              2,029,000               3,016,000
<INCOME-TAX>                                   883,000               1,057,000
<INCOME-CONTINUING>                          1,146,000               1,959,000
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                 1,146,000               1,959,000
<EPS-BASIC>                                     0.14                    0.33
<EPS-DILUTED>                                     0.13                    0.29
<FN>
<F1>THE COMPARATIVE FINANCIAL INFORMATION CONTAINED IN THIS SCHEDULE HAS BEEN
RESTATED TO REFLECT THE OCTOBER 28, 1997 MERGER WITH WESTERN TELECOM
CONSTRUCTION LTD., THE MAY 29, 1998 MERGER WITH MJA COMMUNICATIONS CORP., AND
THE AUGUST 31, 1998 MERGER WITH STANDBY SERVICES, INC., ALL OF WHICH WERE
ACCOUNTED FOR AS POOLINGS-OF-INTERESTS.
<F2>OTHER EQUITY OF $44,816,000 AT MARCH 31, 1999 IS COMPRISED OF ADDITIONAL
PAID-IN CAPITAL OF $39,488,000, ACCUMULATED OTHER COMPREHENSIVE INCOME OF
$(482,000) AND RETAINED EARNINGS OF $5,810,000.
<F3>DATA TO COME
</FN>


</TABLE>