The Enter key can be set to jump to the same field in the next record.
Check the options under
Tools->Options->Keyboard->Move After Enter
Change it to Next Record.

Potentially, you could change this setting in code:
'aircode

Dim intOldOption as integer

'in Subform gotfocus
intOldOption = GetOption("Move After Enter")
SetOption "Move After Enter", 2

'in Subform LostFocus
setOption "Move After Enter", intOldOption

------
but be warned, some users really don't like their settings to be changed

HTH,

Kevin

If you are willing to allow the user to use the up arrow and down arrow keys
to move between records and remain in the same control then here is a routine
that will work:

Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
Dim lngRecords As Long
Dim lngPosition As Long

   lngRecords = Me.Recordset.RecordCount - 1
   lngPosition = Me.Recordset.AbsolutePosition
   If KeyCode = vbKeyUp Then
       If lngPosition <> 0 Then
           Me.Recordset.MovePrevious
       Else
           KeyCode = 0
       End If
   ElseIf KeyCode = vbKeyDown Then
       If lngPosition = lngRecords Then
           KeyCode = 0
       Else
           Me.Recordset.MoveNext
       End If
   End If
   
End Sub

It requires that the form's KeyPreview property be set to Yes so the form
will see the keystroke before the control.  The reason for the KeyCode = 0 is
that if you are on the first record and press the up arrow, it will move to
the previous control on the same record.  Setting the KeyCode to 0 makes the
control think no key had been pressed, so it just stays on the first record
in the same control.  The same is true of the last record with the down arrow
key.