Bear is the first to be seen in beach (5)
I believe the answer is:
stand
'bear' is the definition.
(I know that bear can be written as stand)
'the first to be seen in beach' is the wordplay.
'the first to' becomes 't' (1st letter of 'to').
'be seen in' means one lot of letters goes inside another.
'beach' becomes 'sand'.
't' inserted inside 'sand' is 'STAND'.
'is' is the link.
(Other definitions for stand that I've seen before include "stay the same in position" , "Remain upright" , "Sit here at a sports event" , "group of trees" , "Decline to interfere when one should?" .)