<TABLE> <S> <C>

<ARTICLE> 6
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY INFORMATION EXTRACTED FROM JOHN HANCOCK VARIABLE
SERIES TRUST I AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL
STATEMENTS.
</LEGEND>
<CIK> 0000785303
<NAME> JOHN HANCOCK VARIABLE SERIES TRUST I
<SERIES>
   <NUMBER> 02
   <NAME> SOVEREIGN BOND
<MULTIPLIER> 1000
       
<S>                             <C>
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               JUN-30-1998
<INVESTMENTS-AT-COST>                          780,426
<INVESTMENTS-AT-VALUE>                         853,870
<RECEIVABLES>                                   24,311
<ASSETS-OTHER>                                       0
<OTHER-ITEMS-ASSETS>                             1,894
<TOTAL-ASSETS>                                 880,075
<PAYABLE-FOR-SECURITIES>                        34,772
<SENIOR-LONG-TERM-DEBT>                              0
<OTHER-ITEMS-LIABILITIES>                          130
<TOTAL-LIABILITIES>                             34,902
<SENIOR-EQUITY>                                      0
<PAID-IN-CAPITAL-COMMON>                       811,136
<SHARES-COMMON-STOCK>                           84,361
<SHARES-COMMON-PRIOR>                                0
<ACCUMULATED-NII-CURRENT>                        4,213
<OVERDISTRIBUTION-NII>                               0
<ACCUMULATED-NET-GAINS>                          4,281
<OVERDISTRIBUTION-GAINS>                             0
<ACCUM-APPREC-OR-DEPREC>                        25,543
<NET-ASSETS>                                   845,173
<DIVIDEND-INCOME>                                    0
<INTEREST-INCOME>                               29,837
<OTHER-INCOME>                                       0
<EXPENSES-NET>                                   1,150
<NET-INVESTMENT-INCOME>                         28,687
<REALIZED-GAINS-CURRENT>                         4,281
<APPREC-INCREASE-CURRENT>                        1,400
<NET-CHANGE-FROM-OPS>                           34,368
<EQUALIZATION>                                       0
<DISTRIBUTIONS-OF-INCOME>                     (28,687)
<DISTRIBUTIONS-OF-GAINS>                             0
<DISTRIBUTIONS-OTHER>                                0
<NUMBER-OF-SHARES-SOLD>                          4,508
<NUMBER-OF-SHARES-REDEEMED>                    (3,809)
<SHARES-REINVESTED>                              2,873
<NET-CHANGE-IN-ASSETS>                          41,403
<ACCUMULATED-NII-PRIOR>                              0
<ACCUMULATED-GAINS-PRIOR>                            0
<OVERDISTRIB-NII-PRIOR>                              0
<OVERDIST-NET-GAINS-PRIOR>                           0
<GROSS-ADVISORY-FEES>                            1,023
<INTEREST-EXPENSE>                                   0
<GROSS-EXPENSE>                                  1,150
<AVERAGE-NET-ASSETS>                                 0
<PER-SHARE-NAV-BEGIN>                             9.95
<PER-SHARE-NII>                                   0.35
<PER-SHARE-GAIN-APPREC>                           0.07
<PER-SHARE-DIVIDEND>                            (0.35)
<PER-SHARE-DISTRIBUTIONS>                            0
<RETURNS-OF-CAPITAL>                                 0
<PER-SHARE-NAV-END>                              10.02
<EXPENSE-RATIO>                                   0.28
<AVG-DEBT-OUTSTANDING>                               0
<AVG-DEBT-PER-SHARE>                                 0
        

</TABLE>