A systematic study of the use in “batch equilibration” of pretreated solid Chelex-100 and Lewatit TP 207 (H + form) for the preconcentration of Cr(III), Cu(II) and Mn(II) dissolved in sea water is presented. The preparation of the resin and the suggested procedure are useful because sea water can be treated immediately after sampling, which is very important with regard to speciation analysis. A comparison between Chelex-100 and Lewatit TP 207 resins shoed that the macroporous Lewatit TP 207 is able to recover both the colloidal form and the free dissolved ionic form of Cr(III). For Cu(II) the use of both exchangers on two sea water subsamples will give useful information, whereas for Mn(II) the choice of Chelex-100 or Lewatit TP 207 is immaterial.